diff --git a/examples/audience/Assets/SampleApp/Scripts/AudienceSample.UI.cs b/examples/audience/Assets/SampleApp/Scripts/AudienceSample.UI.cs
index 5b0a81c48..9df2e7bd6 100644
--- a/examples/audience/Assets/SampleApp/Scripts/AudienceSample.UI.cs
+++ b/examples/audience/Assets/SampleApp/Scripts/AudienceSample.UI.cs
@@ -365,7 +365,7 @@ private void RegisterHandlers()
                     if (label.ClassListContains(SampleAppUi.Css.Copied)) return;
                     if (string.IsNullOrEmpty(label.text) || label.text == SampleAppUi.StatusBar.EmptyText) return;
                     GUIUtility.systemCopyBuffer = label.text;
-                    label.text = "Copied!";
+                    label.text = SampleAppUi.ButtonText.CopiedFlash;
                     FlashCopied(label);
                 });
         }
@@ -533,17 +533,17 @@ private void RefreshStatusBar()
             string? derivedFromKey = keyEmpty ? null : (isTest ? Constants.SandboxBaseUrl : Constants.ProductionBaseUrl);
             string? endpoint = hasOverride ? overrideUrl : derivedFromKey;
             bool warnState = hasOverride || (!keyEmpty && !isTest);
-            SetStatusCell(_statusEndpoint, endpoint, warnState ? "state-warn" : "state-ok");
+            SetStatusCell(_statusEndpoint, endpoint, warnState ? SampleAppUi.Css.StateWarn : SampleAppUi.Css.StateOk);
             _prodWarning.EnableInClassList(SampleAppUi.HiddenClass, hasOverride || keyEmpty || isTest);
 
             var consent = _initialised ? ImmutableAudience.CurrentConsent : ConsentOrder[Mathf.Clamp(_initialConsent?.index ?? 0, 0, ConsentOrder.Length - 1)];
             int cIdx = Array.IndexOf(ConsentOrder, consent);
-            SetStatusCell(_statusConsent, consent.ToLowercaseString(), cIdx >= 0 ? ConsentStateClass[cIdx] : "dim");
+            SetStatusCell(_statusConsent, consent.ToLowercaseString(), cIdx >= 0 ? ConsentStateClass[cIdx] : SampleAppUi.Css.Dim);
 
-            SetStatusCell(_statusAnon,    _initialised ? ImmutableAudience.AnonymousId : null, "dim");
-            SetStatusCell(_statusUser,    _initialised ? ImmutableAudience.UserId      : null, "dim");
-            SetStatusCell(_statusSession, _initialised ? ImmutableAudience.SessionId   : null, "dim");
-            SetStatusCell(_statusQueue,   _initialised ? ImmutableAudience.QueueSize.ToString(CultureInfo.InvariantCulture) : null, "dim");
+            SetStatusCell(_statusAnon,    _initialised ? ImmutableAudience.AnonymousId : null, SampleAppUi.Css.Dim);
+            SetStatusCell(_statusUser,    _initialised ? ImmutableAudience.UserId      : null, SampleAppUi.Css.Dim);
+            SetStatusCell(_statusSession, _initialised ? ImmutableAudience.SessionId   : null, SampleAppUi.Css.Dim);
+            SetStatusCell(_statusQueue,   _initialised ? ImmutableAudience.QueueSize.ToString(CultureInfo.InvariantCulture) : null, SampleAppUi.Css.Dim);
         }
 
         private void RefreshConsentPills()
diff --git a/examples/audience/Assets/SampleApp/Scripts/AudienceSample.cs b/examples/audience/Assets/SampleApp/Scripts/AudienceSample.cs
index 6a16d7626..26f7c3807 100644
--- a/examples/audience/Assets/SampleApp/Scripts/AudienceSample.cs
+++ b/examples/audience/Assets/SampleApp/Scripts/AudienceSample.cs
@@ -71,7 +71,7 @@ private void OnShutdown() => RunAndLog(SampleAppUi.LogLabels.Shutdown, () =>
             _initialised = false;
             ResetIdentityMirror();
             OnSdkStateChanged();
-            return "SDK stopped";
+            return SampleAppUi.Messages.SdkStopped;
         });
 
         private void OnReset() => RunAndLog(SampleAppUi.LogLabels.Reset, () =>
@@ -79,22 +79,22 @@ private void OnReset() => RunAndLog(SampleAppUi.LogLabels.Reset, () =>
             ImmutableAudience.Reset();
             ResetIdentityMirror();
             OnSdkStateChanged();
-            return "anonymous ID regenerated, queue cleared";
+            return SampleAppUi.Messages.AnonymousIdRegeneratedQueueCleared;
         });
 
         private async Task OnFlushAsync()
         {
-            try { await ImmutableAudience.FlushAsync(); AppendLog(SampleAppUi.LogLabels.Flush, "queue flushed", LogLevel.Ok, LogSource.App); OnSdkStateChanged(); }
+            try { await ImmutableAudience.FlushAsync(); AppendLog(SampleAppUi.LogLabels.Flush, SampleAppUi.Messages.QueueFlushed, LogLevel.Ok, LogSource.App); OnSdkStateChanged(); }
             catch (Exception ex) { AppendLog(SampleAppUi.LogLabels.Flush, ex.Message, LogLevel.Err, LogSource.App); }
         }
 
         private async Task OnDeleteDataAsync()
         {
-            AppendLog(SampleAppUi.LogLabels.DeleteData, "erasure request dispatched", LogLevel.Info, LogSource.App);
+            AppendLog(SampleAppUi.LogLabels.DeleteData, SampleAppUi.Messages.ErasureRequestDispatched, LogLevel.Info, LogSource.App);
             try
             {
                 await ImmutableAudience.DeleteData();
-                AppendLog(SampleAppUi.LogLabels.DeleteData, "backend acknowledged", LogLevel.Ok, LogSource.App);
+                AppendLog(SampleAppUi.LogLabels.DeleteData, SampleAppUi.Messages.BackendAcknowledged, LogLevel.Ok, LogSource.App);
             }
             catch (Exception ex)
             {
@@ -130,8 +130,8 @@ private void OnSendCatalogueEvent(EventSpec spec, Dictionary<string, VisualEleme
                     ImmutableAudience.Track(typed);
                     return Json.Serialize(new Dictionary<string, object>
                     {
-                        ["event"] = spec.Name,
-                        ["overload"] = "typed",
+                        [SampleAppUi.LogPayloadKeys.Event] = spec.Name,
+                        [SampleAppUi.LogPayloadKeys.Overload] = SampleAppUi.LogPayloadKeys.OverloadValues.Typed,
                         [MessageFields.Properties] = typed.ToProperties(),
                     }, 2);
                 }
@@ -139,8 +139,8 @@ private void OnSendCatalogueEvent(EventSpec spec, Dictionary<string, VisualEleme
                 ImmutableAudience.Track(spec.Name, props.Count > 0 ? props : null);
                 return Json.Serialize(new Dictionary<string, object>
                 {
-                    ["event"] = spec.Name,
-                    ["overload"] = "string",
+                    [SampleAppUi.LogPayloadKeys.Event] = spec.Name,
+                    [SampleAppUi.LogPayloadKeys.Overload] = SampleAppUi.LogPayloadKeys.OverloadValues.String,
                     [MessageFields.Properties] = props,
                 }, 2);
             });
@@ -154,7 +154,7 @@ private void OnSendCustomEvent() => RunAndLog(SampleAppUi.LogLabels.Track, () =>
             var f = CaptureCustomEventForm();
             var props = string.IsNullOrEmpty(f.RawProps) ? null : JsonReader.DeserializeObject(f.RawProps);
             ImmutableAudience.Track(f.Name, props);
-            var echo = new Dictionary<string, object> { ["event"] = f.Name };
+            var echo = new Dictionary<string, object> { [SampleAppUi.LogPayloadKeys.Event] = f.Name };
             if (props != null) echo[MessageFields.Properties] = props;
             return Json.Serialize(echo, 2);
         });
@@ -171,14 +171,14 @@ private void OnSetConsent(ConsentLevel level) => RunAndLog(SampleAppUi.LogLabels
             if (!level.CanIdentify()) ResetIdentityMirror();
             var payload = new Dictionary<string, object>
             {
-                ["from"] = previous.ToLowercaseString(),
-                ["to"] = level.ToLowercaseString(),
+                [SampleAppUi.LogPayloadKeys.From] = previous.ToLowercaseString(),
+                [SampleAppUi.LogPayloadKeys.To] = level.ToLowercaseString(),
             };
             var effects = new List<string>();
             if (previous == ConsentLevel.None && level != ConsentLevel.None) effects.Add(SampleAppUi.Messages.QueueStartedSessionCreated);
             if (level == ConsentLevel.None) effects.Add(SampleAppUi.Messages.QueuePurgedAnonymousIdCleared);
             if (!level.CanIdentify() && previous.CanIdentify()) effects.Add(SampleAppUi.Messages.UserIdCleared);
-            if (effects.Count > 0) payload["effects"] = effects;
+            if (effects.Count > 0) payload[SampleAppUi.LogPayloadKeys.Effects] = effects;
             OnSdkStateChanged();
             return Json.Serialize(payload, 2);
         });
@@ -198,9 +198,9 @@ private void OnIdentify() => RunAndLog(SampleAppUi.LogLabels.Identify, () =>
             OnSdkStateChanged();
             var payload = new Dictionary<string, object>
             {
-                ["id"]                       = f.Id,
-                [MessageFields.IdentityType] = f.Type,
-                ["accepted"]                 = accepted,
+                [SampleAppUi.LogPayloadKeys.Id]       = f.Id,
+                [MessageFields.IdentityType]          = f.Type,
+                [SampleAppUi.LogPayloadKeys.Accepted] = accepted,
             };
             if (traits != null) payload[MessageFields.Traits] = traits;
             return Json.Serialize(payload, 2);
@@ -233,9 +233,9 @@ private void OnAlias() => RunAndLog(SampleAppUi.LogLabels.Alias, () =>
             }
             return Json.Serialize(new Dictionary<string, object>
             {
-                ["from"]     = new Dictionary<string, object> { ["id"] = f.FromId, [MessageFields.IdentityType] = f.FromType },
-                ["to"]       = new Dictionary<string, object> { ["id"] = f.ToId,   [MessageFields.IdentityType] = f.ToType },
-                ["accepted"] = accepted,
+                [SampleAppUi.LogPayloadKeys.From]     = new Dictionary<string, object> { [SampleAppUi.LogPayloadKeys.Id] = f.FromId, [MessageFields.IdentityType] = f.FromType },
+                [SampleAppUi.LogPayloadKeys.To]       = new Dictionary<string, object> { [SampleAppUi.LogPayloadKeys.Id] = f.ToId,   [MessageFields.IdentityType] = f.ToType },
+                [SampleAppUi.LogPayloadKeys.Accepted] = accepted,
             }, 2);
         });
 
@@ -246,8 +246,8 @@ private void OnAlias() => RunAndLog(SampleAppUi.LogLabels.Alias, () =>
         private void OnSdkError(AudienceError err) =>
             AppendLog(SampleAppUi.LogLabels.OnError, Json.Serialize(new Dictionary<string, object>
             {
-                ["code"] = err.Code.ToString(),
-                ["message"] = err.Message,
+                [SampleAppUi.LogPayloadKeys.Code] = err.Code.ToString(),
+                [SampleAppUi.LogPayloadKeys.Message] = err.Message,
             }, 2), LogLevel.Err, LogSource.Sdk);
 
         // SDK Log.Writer adapter. May fire from any thread; AppendLog handles
@@ -288,7 +288,7 @@ private static void GuardConsentForTrack()
             var consent = ImmutableAudience.CurrentConsent;
             if (!consent.CanTrack())
                 throw new InvalidOperationException(
-                    $"track dropped — consent is {consent.ToLowercaseString()}; raise to anonymous or full to queue events");
+                    string.Format(SampleAppUi.Messages.TrackDroppedConsentFmt, consent.ToLowercaseString()));
         }
 
         // Refresh* are idempotent reads, so calling all four every time is
@@ -320,7 +320,7 @@ private AudienceConfig BuildAudienceConfig(InitForm form, Action<AudienceError>
             if (form.FlushIntervalMs is int flushMs && flushMs > 0)
             {
                 if (flushMs < 1000)
-                    AppendLog(SampleAppUi.LogLabels.Init, $"flushInterval {flushMs}ms below 1s — clamped", LogLevel.Warn, LogSource.App);
+                    AppendLog(SampleAppUi.LogLabels.Init, string.Format(SampleAppUi.Messages.FlushIntervalBelowOneSecondClampedFmt, flushMs), LogLevel.Warn, LogSource.App);
                 config.FlushIntervalSeconds = Math.Max(1, flushMs / 1000);
             }
             if (form.FlushSize is int flushSize && flushSize > 0)
@@ -334,17 +334,17 @@ private static Dictionary<string, object> BuildConfigEcho(AudienceConfig config)
         {
             var echo = new Dictionary<string, object>
             {
-                ["consent"]                = config.Consent.ToString(),
-                ["debug"]                  = config.Debug,
-                ["flushIntervalSeconds"]   = config.FlushIntervalSeconds,
-                ["flushSize"]              = config.FlushSize,
-                ["packageVersion"]         = config.PackageVersion,
-                ["shutdownFlushTimeoutMs"] = config.ShutdownFlushTimeoutMs,
+                [SampleAppUi.LogPayloadKeys.Consent]                = config.Consent.ToString(),
+                [SampleAppUi.LogPayloadKeys.Debug]                  = config.Debug,
+                [SampleAppUi.LogPayloadKeys.FlushIntervalSeconds]   = config.FlushIntervalSeconds,
+                [SampleAppUi.LogPayloadKeys.FlushSize]              = config.FlushSize,
+                [SampleAppUi.LogPayloadKeys.PackageVersion]         = config.PackageVersion,
+                [SampleAppUi.LogPayloadKeys.ShutdownFlushTimeoutMs] = config.ShutdownFlushTimeoutMs,
             };
             if (!string.IsNullOrEmpty(config.PublishableKey))
-                echo["publishableKey"] = RedactPublishableKey(config.PublishableKey);
+                echo[SampleAppUi.LogPayloadKeys.PublishableKey] = RedactPublishableKey(config.PublishableKey);
             if (!string.IsNullOrEmpty(config.PersistentDataPath))
-                echo["persistentDataPath"] = config.PersistentDataPath;
+                echo[SampleAppUi.LogPayloadKeys.PersistentDataPath] = config.PersistentDataPath;
             return echo;
         }
 
diff --git a/examples/audience/Assets/SampleApp/Scripts/SampleAppUi.cs b/examples/audience/Assets/SampleApp/Scripts/SampleAppUi.cs
index e48ff4d9a..d842cf876 100644
--- a/examples/audience/Assets/SampleApp/Scripts/SampleAppUi.cs
+++ b/examples/audience/Assets/SampleApp/Scripts/SampleAppUi.cs
@@ -160,6 +160,10 @@ internal static class ButtonText
             internal const string Send = "Send";
             internal const string Copy = "Copy";
             internal const string Copied = "Copied";
+
+            // Click-to-copy flash on status cells (transient label override).
+            // Distinct from Copied which is the post-click button label.
+            internal const string CopiedFlash = "Copied!";
         }
 
         // ---- Resources paths ----
@@ -182,9 +186,22 @@ internal static class Messages
             internal const string QueueStartedSessionCreated = "queue started, session created";
             internal const string QueuePurgedAnonymousIdCleared = "queue purged, anonymous ID cleared";
             internal const string UserIdCleared = "userId cleared";
-            internal const string NoActiveIdentity = "no active identity — call Identify first";
+            internal const string NoActiveIdentity = "no active identity, call Identify first";
             internal const string TraitsRequired = "traits required";
             internal const string Ready = "Sample app loaded. Paste a publishable key and click Init.";
+
+            // Status messages emitted by AudienceSample's RunAndLog handlers.
+            internal const string SdkStopped = "SDK stopped";
+            internal const string AnonymousIdRegeneratedQueueCleared = "anonymous ID regenerated, queue cleared";
+            internal const string QueueFlushed = "queue flushed";
+            internal const string ErasureRequestDispatched = "erasure request dispatched";
+            internal const string BackendAcknowledged = "backend acknowledged";
+
+            // Formatted variants for use with string.Format or interpolation.
+            internal const string TrackDroppedConsentFmt =
+                "track dropped, consent is {0}; raise to anonymous or full to queue events";
+            internal const string FlushIntervalBelowOneSecondClampedFmt =
+                "flushInterval {0}ms below 1s, clamped";
         }
 
         // Mirrors AudienceSample.UI.cs PopulateTypedEventAccordions naming:
@@ -301,5 +318,42 @@ internal static class Consent
             internal const string Anonymous = "anonymous";
             internal const string Full = "full";
         }
+
+        // Log payload JSON keys used by RunAndLog "Ok" row dictionaries.
+
+        internal static class LogPayloadKeys
+        {
+            // Track outcomes
+            internal const string Event = "event";
+            internal const string Overload = "overload";
+            internal const string Effects = "effects";
+
+            // Identify / Alias outcomes
+            internal const string Id = "id";
+            internal const string Accepted = "accepted";
+            internal const string From = "from";
+            internal const string To = "to";
+
+            // OnError row payload
+            internal const string Code = "code";
+            internal const string Message = "message";
+
+            // Init config echo
+            internal const string Consent = "consent";
+            internal const string Debug = "debug";
+            internal const string FlushIntervalSeconds = "flushIntervalSeconds";
+            internal const string FlushSize = "flushSize";
+            internal const string PackageVersion = "packageVersion";
+            internal const string ShutdownFlushTimeoutMs = "shutdownFlushTimeoutMs";
+            internal const string PublishableKey = "publishableKey";
+            internal const string PersistentDataPath = "persistentDataPath";
+
+            // Track overload values.
+            internal static class OverloadValues
+            {
+                internal const string Typed = "typed";
+                internal const string String = "string";
+            }
+        }
     }
 }
diff --git a/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireFixtures.cs b/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireFixtures.cs
new file mode 100644
index 000000000..a642eb2f9
--- /dev/null
+++ b/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireFixtures.cs
@@ -0,0 +1,10 @@
+namespace Immutable.Audience.Samples.SampleApp.Tests
+{
+    // Values used by SampleAppLiveFireTests when filling the demo input fields.
+    internal static class SampleAppLiveFireFixtures
+    {
+        internal const string MilestoneSmokeName = "il2cpp_smoke";
+        internal const string GameId = "il2cpp_game_1";
+        internal const string LinkUrl = "https://example.com/il2cpp";
+    }
+}
diff --git a/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireFixtures.cs.meta b/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireFixtures.cs.meta
new file mode 100644
index 000000000..fab7470eb
--- /dev/null
+++ b/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireFixtures.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 7e230edd97bb4848af6b5988e961d01c
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData:
+  assetBundleName:
+  assetBundleVariant:
diff --git a/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireTests.cs b/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireTests.cs
index 2682fb149..1565cca1d 100644
--- a/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireTests.cs
+++ b/examples/audience/Assets/SampleApp/Tests/Runtime/SampleAppLiveFireTests.cs
@@ -172,7 +172,7 @@ public IEnumerator TypedEvent_MilestoneReached_FlushReportsOk()
         {
             yield return DriveTypedEventAndFlush(SampleAppUi.Buttons.TypedEvent(EventNames.MilestoneReached), root =>
             {
-                root.Q<TextField>(SampleAppUi.TypedEventField(EventNames.MilestoneReached, EventPropertyKeys.Name)).value = "il2cpp_smoke";
+                root.Q<TextField>(SampleAppUi.TypedEventField(EventNames.MilestoneReached, EventPropertyKeys.Name)).value = SampleAppLiveFireFixtures.MilestoneSmokeName;
             });
         }
 
@@ -262,7 +262,7 @@ public IEnumerator CustomTrack_WithDictionaryProps_FlushReportsOk()
 
             // Custom event name + JSON props (the sample app parses props as JSON
             // and forwards them as Dictionary<string, object> to ImmutableAudience.Track).
-            _root!.Q<TextField>(SampleAppUi.CustomEvent.Name).value = "il2cpp_smoke";
+            _root!.Q<TextField>(SampleAppUi.CustomEvent.Name).value = SampleAppLiveFireFixtures.MilestoneSmokeName;
             _root.Q<TextField>(SampleAppUi.CustomEvent.Props).value =
                 "{\"int_field\":42,\"str_field\":\"hello\",\"bool_field\":true,\"nested\":{\"a\":1}}";
             _root.Q<Button>(SampleAppUi.Buttons.CustomEvent).Click();
@@ -423,7 +423,7 @@ public IEnumerator TypedEvent_WishlistAdd_FlushReportsOk()
         {
             yield return DriveTypedEventAndFlush(SampleAppUi.Buttons.TypedEvent(SampleAppCustomEvents.WishlistAdd), root =>
             {
-                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.WishlistAdd, SampleAppCustomEventPropertyKeys.GameId)).value = "il2cpp_game_1";
+                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.WishlistAdd, SampleAppCustomEventPropertyKeys.GameId)).value = SampleAppLiveFireFixtures.GameId;
             });
         }
 
@@ -432,7 +432,7 @@ public IEnumerator TypedEvent_WishlistRemove_FlushReportsOk()
         {
             yield return DriveTypedEventAndFlush(SampleAppUi.Buttons.TypedEvent(SampleAppCustomEvents.WishlistRemove), root =>
             {
-                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.WishlistRemove, SampleAppCustomEventPropertyKeys.GameId)).value = "il2cpp_game_1";
+                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.WishlistRemove, SampleAppCustomEventPropertyKeys.GameId)).value = SampleAppLiveFireFixtures.GameId;
             });
         }
 
@@ -441,7 +441,7 @@ public IEnumerator TypedEvent_GamePageViewed_FlushReportsOk()
         {
             yield return DriveTypedEventAndFlush(SampleAppUi.Buttons.TypedEvent(SampleAppCustomEvents.GamePageViewed), root =>
             {
-                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.GamePageViewed, SampleAppCustomEventPropertyKeys.GameId)).value = "il2cpp_game_1";
+                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.GamePageViewed, SampleAppCustomEventPropertyKeys.GameId)).value = SampleAppLiveFireFixtures.GameId;
             });
         }
 
@@ -450,7 +450,7 @@ public IEnumerator TypedEvent_LinkClicked_FlushReportsOk()
         {
             yield return DriveTypedEventAndFlush(SampleAppUi.Buttons.TypedEvent(SampleAppCustomEvents.LinkClicked), root =>
             {
-                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.LinkClicked, SampleAppCustomEventPropertyKeys.Url)).value = "https://example.com/il2cpp";
+                root.Q<TextField>(SampleAppUi.TypedEventField(SampleAppCustomEvents.LinkClicked, SampleAppCustomEventPropertyKeys.Url)).value = SampleAppLiveFireFixtures.LinkUrl;
             });
         }
 
diff --git a/src/Packages/Audience/Tests/Runtime/ConstantsTests.cs b/src/Packages/Audience/Tests/Runtime/ConstantsTests.cs
index 223b88057..37909566c 100644
--- a/src/Packages/Audience/Tests/Runtime/ConstantsTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/ConstantsTests.cs
@@ -6,6 +6,19 @@ namespace Immutable.Audience.Tests
     [TestFixture]
     internal class ConstantsTests
     {
+        // Publishable key fixtures used by the BaseUrl resolution tests.
+        private const string TestPrefixKeyFixture = "pk_imapik-test-abc";
+        private const string ProdPrefixKeyFixture = "pk_imapik-prod-abc";
+        private const string CustomBaseUrlOverride = "https://api.dev.immutable.com";
+
+        // package.json upward-walk components and the JSON fields parsed back.
+        private const string SrcDirectoryName = "src";
+        private const string PackagesDirectoryName = "Packages";
+        private const string AudiencePackageDirectoryName = "Audience";
+        private const string PackageJsonFileName = "package.json";
+        private const string PackageJsonVersionField = "version";
+        private const string PackageJsonNameField = "name";
+
         // -----------------------------------------------------------------
         // BaseUrl resolution
         // -----------------------------------------------------------------
@@ -14,14 +27,14 @@ internal class ConstantsTests
         public void BaseUrl_TestKey_ResolvesToSandbox()
         {
             Assert.AreEqual(Constants.SandboxBaseUrl,
-                Constants.BaseUrl("pk_imapik-test-abc"));
+                Constants.BaseUrl(TestPrefixKeyFixture));
         }
 
         [Test]
         public void BaseUrl_NonTestKey_ResolvesToProduction()
         {
             Assert.AreEqual(Constants.ProductionBaseUrl,
-                Constants.BaseUrl("pk_imapik-prod-abc"));
+                Constants.BaseUrl(ProdPrefixKeyFixture));
         }
 
         [Test]
@@ -36,9 +49,8 @@ public void BaseUrl_Override_WinsOverKeyPrefix()
         {
             // Override wins even for a test-prefixed key that would
             // otherwise derive to Sandbox.
-            const string custom = "https://api.dev.immutable.com";
-            Assert.AreEqual(custom,
-                Constants.BaseUrl("pk_imapik-test-abc", custom));
+            Assert.AreEqual(CustomBaseUrlOverride,
+                Constants.BaseUrl(TestPrefixKeyFixture, CustomBaseUrlOverride));
         }
 
         [Test]
@@ -47,7 +59,7 @@ public void BaseUrl_EmptyOverride_FallsBackToKeyDerivation()
             // Empty-string override is treated as "no override" so the
             // key-prefix fallback still kicks in.
             Assert.AreEqual(Constants.SandboxBaseUrl,
-                Constants.BaseUrl("pk_imapik-test-abc", ""));
+                Constants.BaseUrl(TestPrefixKeyFixture, ""));
         }
 
         // -----------------------------------------------------------------
@@ -63,7 +75,7 @@ public void LibraryVersion_MatchesPackageJson()
             var packageJson = ReadPackageJson();
             var parsed = JsonReader.DeserializeObject(packageJson);
 
-            Assert.IsTrue(parsed.TryGetValue("version", out var versionObj),
+            Assert.IsTrue(parsed.TryGetValue(PackageJsonVersionField, out var versionObj),
                 "package.json is missing a \"version\" field");
             Assert.AreEqual(Constants.LibraryVersion, versionObj,
                 "Constants.LibraryVersion must match package.json version");
@@ -77,7 +89,7 @@ public void LibraryName_MatchesPackageJson()
             var packageJson = ReadPackageJson();
             var parsed = JsonReader.DeserializeObject(packageJson);
 
-            Assert.IsTrue(parsed.TryGetValue("name", out var nameObj),
+            Assert.IsTrue(parsed.TryGetValue(PackageJsonNameField, out var nameObj),
                 "package.json is missing a \"name\" field");
             Assert.AreEqual(Constants.LibraryName, nameObj,
                 "Constants.LibraryName must match package.json name");
@@ -95,14 +107,14 @@ private static string ReadPackageJson()
             var current = new DirectoryInfo(TestContext.CurrentContext.TestDirectory);
             while (current != null)
             {
-                var candidate = Path.Combine(current.FullName, "src", "Packages", "Audience", "package.json");
+                var candidate = Path.Combine(current.FullName, SrcDirectoryName, PackagesDirectoryName, AudiencePackageDirectoryName, PackageJsonFileName);
                 if (File.Exists(candidate)) return File.ReadAllText(candidate);
 
                 // Also try the direct-inside case (package root itself is
                 // the ancestor), which handles consuming-project layouts
                 // that embed the package without the src/Packages prefix.
-                var direct = Path.Combine(current.FullName, "package.json");
-                if (File.Exists(direct) && current.Name == "Audience") return File.ReadAllText(direct);
+                var direct = Path.Combine(current.FullName, PackageJsonFileName);
+                if (File.Exists(direct) && current.Name == AudiencePackageDirectoryName) return File.ReadAllText(direct);
 
                 current = current.Parent;
             }
diff --git a/src/Packages/Audience/Tests/Runtime/Core/ConsentStoreTests.cs b/src/Packages/Audience/Tests/Runtime/Core/ConsentStoreTests.cs
index 85713b777..313d6bbfc 100644
--- a/src/Packages/Audience/Tests/Runtime/Core/ConsentStoreTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Core/ConsentStoreTests.cs
@@ -50,7 +50,7 @@ public void Load_MalformedFile_ReturnsNull()
             // A garbage value that isn't a valid enum int.
             var dir = AudiencePaths.AudienceDir(_testDir);
             Directory.CreateDirectory(dir);
-            File.WriteAllText(AudiencePaths.ConsentFile(_testDir), "not-an-int");
+            File.WriteAllText(AudiencePaths.ConsentFile(_testDir), TestFixtures.NotAnInt);
 
             Assert.IsNull(ConsentStore.Load(_testDir));
         }
diff --git a/src/Packages/Audience/Tests/Runtime/Core/IdentityTests.cs b/src/Packages/Audience/Tests/Runtime/Core/IdentityTests.cs
index cd2cf5fd6..4a1c33a06 100644
--- a/src/Packages/Audience/Tests/Runtime/Core/IdentityTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Core/IdentityTests.cs
@@ -39,7 +39,7 @@ public void NewDirectory_GeneratesNonEmptyId_AndWritesFile()
         public void ExistingFile_ReturnsPreviousId_WithoutGeneratingNew()
         {
             // Simulate a returning player by pre-writing an identity file (as a previous launch would have done).
-            var expectedId = "pre-existing-id-from-last-launch";
+            var expectedId = TestFixtures.PreExistingIdFromLastLaunch;
             var dir = AudiencePaths.AudienceDir(_testDir);
             Directory.CreateDirectory(dir);
             File.WriteAllText(AudiencePaths.IdentityFile(_testDir), expectedId);
@@ -93,7 +93,7 @@ public void Get_NoExistingFile_ReturnsNull_AndDoesNotCreate()
         [Test]
         public void Get_ExistingFile_ReturnsPersistedId()
         {
-            var expectedId = "pre-existing-id";
+            var expectedId = TestFixtures.PreExistingId;
             var dir = AudiencePaths.AudienceDir(_testDir);
             Directory.CreateDirectory(dir);
             File.WriteAllText(AudiencePaths.IdentityFile(_testDir), expectedId);
diff --git a/src/Packages/Audience/Tests/Runtime/DeleteDataTests.cs b/src/Packages/Audience/Tests/Runtime/DeleteDataTests.cs
index 0daa64807..18aed4868 100644
--- a/src/Packages/Audience/Tests/Runtime/DeleteDataTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/DeleteDataTests.cs
@@ -74,7 +74,7 @@ public void DeleteData_WithUserId_FiresDelete_WithUserIdQuery()
             var handler = new CapturingHandler();
             ImmutableAudience.Init(MakeConfig(handler));
 
-            ImmutableAudience.DeleteData(userId: "player-42");
+            ImmutableAudience.DeleteData(userId: TestFixtures.PlayerCustomId);
             WaitForRequest(handler);
 
             // Filter out the game_launch POST from Init.
@@ -136,7 +136,7 @@ public void DeleteData_DoesNotCreateAnonymousIdFile()
             var handler = new CapturingHandler();
             ImmutableAudience.Init(MakeConfig(handler, ConsentLevel.None));
 
-            ImmutableAudience.DeleteData(userId: "some-user");
+            ImmutableAudience.DeleteData(userId: TestFixtures.SomeUser);
             // Even with a userId request, the anonymousId file must not materialise.
             Thread.Sleep(250);
 
@@ -151,7 +151,7 @@ public async Task DeleteData_ReturnsTask_ThatCompletesAfterRequest()
             var handler = new CapturingHandler();
             ImmutableAudience.Init(MakeConfig(handler));
 
-            var task = ImmutableAudience.DeleteData(userId: "player-42");
+            var task = ImmutableAudience.DeleteData(userId: TestFixtures.PlayerCustomId);
             Assert.IsNotNull(task, "DeleteData must return a non-null Task");
 
             // Await directly: no need for the RequestSent gate when the task
@@ -168,7 +168,7 @@ public void DeleteData_BeforeInit_ReturnsCompletedTask()
             // Not initialised: must not throw, must return a completed Task.
             ImmutableAudience.ResetState();
 
-            var task = ImmutableAudience.DeleteData(userId: "player-42");
+            var task = ImmutableAudience.DeleteData(userId: TestFixtures.PlayerCustomId);
 
             Assert.IsNotNull(task);
             Assert.IsTrue(task.IsCompleted, "DeleteData before Init must return an already-completed Task");
@@ -189,7 +189,7 @@ public void DeleteData_ServerError_InvokesOnError()
             };
             ImmutableAudience.Init(config);
 
-            ImmutableAudience.DeleteData(userId: "player-42");
+            ImmutableAudience.DeleteData(userId: TestFixtures.PlayerCustomId);
 
             Assert.IsTrue(received.Wait(TimeSpan.FromSeconds(5)),
                 "OnError should fire when DeleteData's response is non-2xx");
diff --git a/src/Packages/Audience/Tests/Runtime/Events/MessageBuilderTests.cs b/src/Packages/Audience/Tests/Runtime/Events/MessageBuilderTests.cs
index 593f28d0a..abddbc74b 100644
--- a/src/Packages/Audience/Tests/Runtime/Events/MessageBuilderTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Events/MessageBuilderTests.cs
@@ -13,7 +13,7 @@ public class MessageBuilderTests
         [Test]
         public void Track_RequiredFieldsPresent()
         {
-            var result = MessageBuilder.Track(TestEventNames.LevelComplete, "anon-1", null, PackageVersion);
+            var result = MessageBuilder.Track(TestEventNames.LevelComplete, TestFixtures.AnonId1, null, PackageVersion);
 
             Assert.AreEqual(MessageTypes.Track, result[MessageFields.Type]);
             Assert.IsTrue(result.ContainsKey(MessageFields.MessageId));
@@ -36,7 +36,7 @@ public void Track_EventNameLongerThan256Chars_TruncatedTo256()
         [Test]
         public void Track_NullUserId_NotPresentInDict()
         {
-            var result = MessageBuilder.Track("evt", "anon-1", null, PackageVersion);
+            var result = MessageBuilder.Track(TestEventNames.PlaceholderEvt, TestFixtures.AnonId1, null, PackageVersion);
 
             Assert.IsFalse(result.ContainsKey(MessageFields.UserId));
         }
@@ -44,20 +44,20 @@ public void Track_NullUserId_NotPresentInDict()
         [Test]
         public void Track_NonNullUserId_PresentInDict()
         {
-            var result = MessageBuilder.Track("evt", "anon-1", "user-99", PackageVersion);
+            var result = MessageBuilder.Track(TestEventNames.PlaceholderEvt, TestFixtures.AnonId1, TestFixtures.UserId99, PackageVersion);
 
             Assert.IsTrue(result.ContainsKey(MessageFields.UserId));
-            Assert.AreEqual("user-99", result[MessageFields.UserId]);
+            Assert.AreEqual(TestFixtures.UserId99, result[MessageFields.UserId]);
         }
 
         [Test]
         public void Identify_TypeAndIdentityFieldsPresent()
         {
-            var result = MessageBuilder.Identify("anon-42", "user-42", IdentityType.Steam.ToLowercaseString(), PackageVersion);
+            var result = MessageBuilder.Identify(TestFixtures.AnonId42, TestFixtures.UserId42, IdentityType.Steam.ToLowercaseString(), PackageVersion);
 
             Assert.AreEqual(MessageTypes.Identify, result[MessageFields.Type]);
-            Assert.AreEqual("anon-42", result[MessageFields.AnonymousId]);
-            Assert.AreEqual("user-42", result[MessageFields.UserId]);
+            Assert.AreEqual(TestFixtures.AnonId42, result[MessageFields.AnonymousId]);
+            Assert.AreEqual(TestFixtures.UserId42, result[MessageFields.UserId]);
             Assert.AreEqual(IdentityType.Steam.ToLowercaseString(), result[MessageFields.IdentityType]);
         }
 
@@ -65,23 +65,23 @@ public void Identify_TypeAndIdentityFieldsPresent()
         public void Alias_AllFourFieldsPresent()
         {
             var result = MessageBuilder.Alias(
-                "from-id", IdentityType.Email.ToLowercaseString(),
-                "to-id", IdentityType.Steam.ToLowercaseString(),
+                TestFixtures.AliasFromId, IdentityType.Email.ToLowercaseString(),
+                TestFixtures.AliasToId, IdentityType.Steam.ToLowercaseString(),
                 PackageVersion);
 
             Assert.AreEqual(MessageTypes.Alias, result[MessageFields.Type]);
-            Assert.AreEqual("from-id", result[MessageFields.FromId]);
+            Assert.AreEqual(TestFixtures.AliasFromId, result[MessageFields.FromId]);
             Assert.AreEqual(IdentityType.Email.ToLowercaseString(), result[MessageFields.FromType]);
-            Assert.AreEqual("to-id", result[MessageFields.ToId]);
+            Assert.AreEqual(TestFixtures.AliasToId, result[MessageFields.ToId]);
             Assert.AreEqual(IdentityType.Steam.ToLowercaseString(), result[MessageFields.ToType]);
         }
 
         [Test]
         public void AllMessages_ContextContainsLibraryAndLibraryVersion()
         {
-            var track = MessageBuilder.Track("evt", null, null, PackageVersion);
-            var identify = MessageBuilder.Identify(null, "u1", IdentityType.Steam.ToLowercaseString(), PackageVersion);
-            var alias = MessageBuilder.Alias("f", "t1", "t", "t2", PackageVersion);
+            var track = MessageBuilder.Track(TestEventNames.PlaceholderEvt, null, null, PackageVersion);
+            var identify = MessageBuilder.Identify(null, TestFixtures.GenericUserId, IdentityType.Steam.ToLowercaseString(), PackageVersion);
+            var alias = MessageBuilder.Alias(TestFixtures.GenericFromId, TestFixtures.GenericFromType, TestFixtures.GenericToId, TestFixtures.GenericToType, PackageVersion);
 
             foreach (var msg in new[] { track, identify, alias })
             {
@@ -94,9 +94,9 @@ public void AllMessages_ContextContainsLibraryAndLibraryVersion()
         [Test]
         public void AllMessages_SurfaceIsUnity()
         {
-            var track = MessageBuilder.Track("evt", null, null, PackageVersion);
-            var identify = MessageBuilder.Identify(null, "u1", IdentityType.Steam.ToLowercaseString(), PackageVersion);
-            var alias = MessageBuilder.Alias("f", "t1", "t", "t2", PackageVersion);
+            var track = MessageBuilder.Track(TestEventNames.PlaceholderEvt, null, null, PackageVersion);
+            var identify = MessageBuilder.Identify(null, TestFixtures.GenericUserId, IdentityType.Steam.ToLowercaseString(), PackageVersion);
+            var alias = MessageBuilder.Alias(TestFixtures.GenericFromId, TestFixtures.GenericFromType, TestFixtures.GenericToId, TestFixtures.GenericToType, PackageVersion);
 
             Assert.AreEqual(Constants.Surface, track[MessageFields.Surface]);
             Assert.AreEqual(Constants.Surface, identify[MessageFields.Surface]);
@@ -120,7 +120,7 @@ public void Track_MessageId_IsUniquePerCall()
             // Backend deduplicates on messageId; collisions silently drop events.
             var ids = new HashSet<string>();
             for (var i = 0; i < 1000; i++)
-                ids.Add((string)MessageBuilder.Track("evt", null, null, PackageVersion)[MessageFields.MessageId]);
+                ids.Add((string)MessageBuilder.Track(TestEventNames.PlaceholderEvt, null, null, PackageVersion)[MessageFields.MessageId]);
             Assert.AreEqual(1000, ids.Count);
         }
 
@@ -161,9 +161,9 @@ public void AllMessages_Context_LibraryAndLibraryVersionAreNonEmptyStrings()
 
         private static IEnumerable<Dictionary<string, object>> EveryMessageType()
         {
-            yield return MessageBuilder.Track("evt", null, null, PackageVersion);
-            yield return MessageBuilder.Identify(null, "u1", IdentityType.Steam.ToLowercaseString(), PackageVersion);
-            yield return MessageBuilder.Alias("f", "t1", "t", "t2", PackageVersion);
+            yield return MessageBuilder.Track(TestEventNames.PlaceholderEvt, null, null, PackageVersion);
+            yield return MessageBuilder.Identify(null, TestFixtures.GenericUserId, IdentityType.Steam.ToLowercaseString(), PackageVersion);
+            yield return MessageBuilder.Alias(TestFixtures.GenericFromId, TestFixtures.GenericFromType, TestFixtures.GenericToId, TestFixtures.GenericToType, PackageVersion);
         }
     }
 }
diff --git a/src/Packages/Audience/Tests/Runtime/Events/TypedEventTests.cs b/src/Packages/Audience/Tests/Runtime/Events/TypedEventTests.cs
index 82318087b..1cd0ac742 100644
--- a/src/Packages/Audience/Tests/Runtime/Events/TypedEventTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Events/TypedEventTests.cs
@@ -15,7 +15,7 @@ public void Progression_EventName_IsProgression()
         [Test]
         public void Progression_WithoutStatus_ThrowsOnToProperties()
         {
-            var evt = new Progression { World = "tutorial" };
+            var evt = new Progression { World = TestFixtures.ProgressionWorldTutorial };
 
             var ex = Assert.Throws<ArgumentException>(() => evt.ToProperties());
             Assert.That(ex!.Message, Does.Contain("Status"));
@@ -27,7 +27,7 @@ public void Progression_Complete_ProducesCorrectProperties()
             var evt = new Progression
             {
                 Status = ProgressionStatus.Complete,
-                World = "tutorial",
+                World = TestFixtures.ProgressionWorldTutorial,
                 Level = "1",
                 Score = 1500,
                 DurationSec = 120.5f
@@ -36,7 +36,7 @@ public void Progression_Complete_ProducesCorrectProperties()
             var props = evt.ToProperties();
 
             Assert.AreEqual(ProgressionStatus.Complete.ToLowercaseString(), props[EventPropertyKeys.Status]);
-            Assert.AreEqual("tutorial", props[EventPropertyKeys.World]);
+            Assert.AreEqual(TestFixtures.ProgressionWorldTutorial, props[EventPropertyKeys.World]);
             Assert.AreEqual("1", props[EventPropertyKeys.Level]);
             Assert.AreEqual(1500, props[EventPropertyKeys.Score]);
             Assert.AreEqual(120.5f, props[EventPropertyKeys.DurationSec]);
@@ -61,19 +61,19 @@ public void Resource_Source_ProducesCorrectProperties()
             var evt = new Resource
             {
                 Flow = ResourceFlow.Source,
-                Currency = "gold",
+                Currency = TestFixtures.ResourceCurrency,
                 Amount = 100,
-                ItemType = "quest_reward",
-                ItemId = "main_quest_01"
+                ItemType = TestFixtures.ResourceItemType,
+                ItemId = TestFixtures.ResourceItemId
             };
 
             var props = evt.ToProperties();
 
             Assert.AreEqual(ResourceFlow.Source.ToLowercaseString(), props[EventPropertyKeys.Flow]);
-            Assert.AreEqual("gold", props[EventPropertyKeys.Currency]);
+            Assert.AreEqual(TestFixtures.ResourceCurrency, props[EventPropertyKeys.Currency]);
             Assert.AreEqual(100m, props[EventPropertyKeys.Amount]);
-            Assert.AreEqual("quest_reward", props[EventPropertyKeys.ItemType]);
-            Assert.AreEqual("main_quest_01", props[EventPropertyKeys.ItemId]);
+            Assert.AreEqual(TestFixtures.ResourceItemType, props[EventPropertyKeys.ItemType]);
+            Assert.AreEqual(TestFixtures.ResourceItemId, props[EventPropertyKeys.ItemId]);
         }
 
         [Test]
@@ -85,7 +85,7 @@ public void Resource_EventName_IsResource()
         [Test]
         public void Resource_WithoutFlow_ThrowsOnToProperties()
         {
-            var evt = new Resource { Currency = "gold", Amount = 100 };
+            var evt = new Resource { Currency = TestFixtures.ResourceCurrency, Amount = 100 };
 
             var ex = Assert.Throws<ArgumentException>(() => evt.ToProperties());
             Assert.That(ex!.Message, Does.Contain("Flow"));
@@ -103,7 +103,7 @@ public void Resource_WithoutCurrency_ThrowsOnToProperties()
         [Test]
         public void Resource_WithoutAmount_ThrowsOnToProperties()
         {
-            var evt = new Resource { Flow = ResourceFlow.Source, Currency = "gold" };
+            var evt = new Resource { Flow = ResourceFlow.Source, Currency = TestFixtures.ResourceCurrency };
 
             var ex = Assert.Throws<ArgumentException>(() => evt.ToProperties());
             Assert.That(ex!.Message, Does.Contain("Amount"));
@@ -114,28 +114,28 @@ public void Purchase_ProducesCorrectProperties()
         {
             var evt = new Purchase
             {
-                Currency = "USD",
+                Currency = TestFixtures.UsdCurrency,
                 Value = 9.99m,
-                ItemId = "gem_pack_01",
-                ItemName = "Starter Gem Pack",
+                ItemId = TestFixtures.PurchaseItemId,
+                ItemName = TestFixtures.PurchaseItemName,
                 Quantity = 1,
-                TransactionId = "txn_abc123"
+                TransactionId = TestFixtures.PurchaseTransactionId
             };
 
             var props = evt.ToProperties();
 
-            Assert.AreEqual("USD", props[EventPropertyKeys.Currency]);
+            Assert.AreEqual(TestFixtures.UsdCurrency, props[EventPropertyKeys.Currency]);
             Assert.AreEqual(9.99m, props[EventPropertyKeys.Value]);
-            Assert.AreEqual("gem_pack_01", props[EventPropertyKeys.ItemId]);
-            Assert.AreEqual("Starter Gem Pack", props[EventPropertyKeys.ItemName]);
+            Assert.AreEqual(TestFixtures.PurchaseItemId, props[EventPropertyKeys.ItemId]);
+            Assert.AreEqual(TestFixtures.PurchaseItemName, props[EventPropertyKeys.ItemName]);
             Assert.AreEqual(1, props[EventPropertyKeys.Quantity]);
-            Assert.AreEqual("txn_abc123", props[EventPropertyKeys.TransactionId]);
+            Assert.AreEqual(TestFixtures.PurchaseTransactionId, props[EventPropertyKeys.TransactionId]);
         }
 
         [Test]
         public void Purchase_OptionalFieldsOmitted_WhenNull()
         {
-            var props = new Purchase { Currency = "EUR", Value = 5.00m }.ToProperties();
+            var props = new Purchase { Currency = TestFixtures.EurCurrency, Value = 5.00m }.ToProperties();
 
             Assert.IsTrue(props.ContainsKey(EventPropertyKeys.Currency));
             Assert.IsTrue(props.ContainsKey(EventPropertyKeys.Value));
@@ -163,7 +163,7 @@ public void Purchase_WithoutCurrency_ThrowsOnToProperties()
         [Test]
         public void Purchase_WithoutValue_ThrowsOnToProperties()
         {
-            var evt = new Purchase { Currency = "USD" };
+            var evt = new Purchase { Currency = TestFixtures.UsdCurrency };
 
             var ex = Assert.Throws<ArgumentException>(() => evt.ToProperties());
             Assert.That(ex!.Message, Does.Contain("Value"));
@@ -172,9 +172,9 @@ public void Purchase_WithoutValue_ThrowsOnToProperties()
         [Test]
         public void MilestoneReached_ProducesCorrectProperties()
         {
-            var props = new MilestoneReached { Name = "first_boss_defeated" }.ToProperties();
+            var props = new MilestoneReached { Name = TestFixtures.MilestoneName }.ToProperties();
 
-            Assert.AreEqual("first_boss_defeated", props[EventPropertyKeys.Name]);
+            Assert.AreEqual(TestFixtures.MilestoneName, props[EventPropertyKeys.Name]);
             Assert.AreEqual(1, props.Count);
         }
 
diff --git a/src/Packages/Audience/Tests/Runtime/IdentityTypeTests.cs b/src/Packages/Audience/Tests/Runtime/IdentityTypeTests.cs
index 4050e73fe..0ec2de376 100644
--- a/src/Packages/Audience/Tests/Runtime/IdentityTypeTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/IdentityTypeTests.cs
@@ -42,7 +42,7 @@ public void ParseLowercaseString_AcceptsMixedCase(string wire, IdentityType expe
 
         [TestCase(null)]
         [TestCase("")]
-        [TestCase("unknown_provider")]
+        [TestCase(TestFixtures.UnknownProvider)]
         [TestCase("steamX")]
         public void ParseLowercaseString_FallsBackToCustomForUnknownOrEmpty(string? wire)
         {
diff --git a/src/Packages/Audience/Tests/Runtime/ImmutableAudienceTests.cs b/src/Packages/Audience/Tests/Runtime/ImmutableAudienceTests.cs
index 07861159d..7384c56a2 100644
--- a/src/Packages/Audience/Tests/Runtime/ImmutableAudienceTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/ImmutableAudienceTests.cs
@@ -105,8 +105,8 @@ public void UserId_AfterIdentifyAndReset_TracksState()
             Assert.IsNull(ImmutableAudience.UserId,
                 "UserId should be null until Identify is called");
 
-            ImmutableAudience.Identify("player-42", IdentityType.Custom);
-            Assert.AreEqual("player-42", ImmutableAudience.UserId,
+            ImmutableAudience.Identify(TestFixtures.PlayerCustomId, IdentityType.Custom);
+            Assert.AreEqual(TestFixtures.PlayerCustomId, ImmutableAudience.UserId,
                 "UserId must reflect the most recent Identify call");
 
             ImmutableAudience.Reset();
@@ -215,7 +215,7 @@ public void ContextProvider_Set_MergesOnIdentifyPath()
             };
 
             ImmutableAudience.Init(MakeConfig(ConsentLevel.Full));
-            ImmutableAudience.Identify("player-42", IdentityType.Custom);
+            ImmutableAudience.Identify(TestFixtures.PlayerCustomId, IdentityType.Custom);
             ImmutableAudience.Shutdown();
 
             var queueDir = AudiencePaths.QueueDir(_testDir);
@@ -231,7 +231,7 @@ public void ContextProvider_Set_MergesOnIdentifyPath()
         [Test]
         public void ContextProvider_ThrowingDelegate_SwallowsAndShipsBaseContext()
         {
-            ImmutableAudience.ContextProvider = () => throw new InvalidOperationException("boom");
+            ImmutableAudience.ContextProvider = () => throw new InvalidOperationException(TestFixtures.ContextProviderBoomMessage);
 
             ImmutableAudience.Init(MakeConfig());
             ImmutableAudience.Track(TestEventNames.UnitTestEvent);
@@ -319,7 +319,7 @@ public void Track_IEventMissingRequiredField_DropsWithWarn()
             {
                 // Purchase with no Value set: ToProperties throws; Track must
                 // catch, warn, and drop rather than ship an incomplete event.
-                Assert.DoesNotThrow(() => ImmutableAudience.Track(new Purchase { Currency = "USD" }));
+                Assert.DoesNotThrow(() => ImmutableAudience.Track(new Purchase { Currency = TestFixtures.UsdCurrency }));
                 // Assert the stable parts (event-type name and trailing "Dropping")
                 // so the test survives any change to the exception type or message.
                 Assert.That(lines, Has.Some.Contains(nameof(Purchase)));
@@ -408,7 +408,7 @@ public void Alias_InvalidIdentityTypeCast_Throws()
             var invalid = (IdentityType)999;
 
             Assert.Throws<ArgumentOutOfRangeException>(
-                () => ImmutableAudience.Alias("fromId", invalid, "toId", IdentityType.Steam),
+                () => ImmutableAudience.Alias(TestFixtures.GenericAliasFromId, invalid, TestFixtures.GenericAliasToId, IdentityType.Steam),
                 "invalid enum cast must throw so a broken alias call fails loud rather " +
                 "than shipping an event that cannot be matched for deletion");
         }
@@ -419,7 +419,7 @@ public void Alias_NullIds_DoesNotEnqueue()
             ImmutableAudience.Init(MakeConfig(ConsentLevel.Full));
 
             Assert.DoesNotThrow(() => ImmutableAudience.Alias(null, IdentityType.Passport, "to", IdentityType.Steam));
-            Assert.DoesNotThrow(() => ImmutableAudience.Alias("from", IdentityType.Passport, "", IdentityType.Steam));
+            Assert.DoesNotThrow(() => ImmutableAudience.Alias(TestFixtures.GenericAliasFromShort, IdentityType.Passport, "", IdentityType.Steam));
         }
 
         [Test]
@@ -490,7 +490,7 @@ public void Track_CustomEvent_WritesEventToDisk()
 
             ImmutableAudience.Track(TestEventNames.CraftingStarted, new Dictionary<string, object>
             {
-                { "recipe_id", "iron_sword" }
+                { TestFixtures.CustomPropKeyRecipeId, TestFixtures.CraftingRecipeIronSword }
             });
 
             // Flush memory → disk
@@ -581,7 +581,7 @@ public void Track_TypedProgression_WritesCorrectEventName()
             ImmutableAudience.Track(new Progression
             {
                 Status = ProgressionStatus.Complete,
-                World = "tutorial",
+                World = TestFixtures.ProgressionWorldTutorial,
                 Level = "1"
             });
             ImmutableAudience.Shutdown();
@@ -600,7 +600,7 @@ public void Track_TypedPurchase_WritesCorrectEventName()
 
             ImmutableAudience.Track(new Purchase
             {
-                Currency = "USD",
+                Currency = TestFixtures.UsdCurrency,
                 Value = 9.99m
             });
             ImmutableAudience.Shutdown();
@@ -968,7 +968,7 @@ public void SetConsent_DowngradeToAnonymous_StressTest_NoUserIdLeak()
             // EnqueueTrack and this test leaks reproducibly.
             const int iterations = 200;
             const int trackersPerIteration = 4;
-            const string testUserId = "user_race_stress";
+            const string testUserId = TestFixtures.UserRaceStress;
 
             for (int iter = 0; iter < iterations; iter++)
             {
@@ -1124,7 +1124,7 @@ public void Init_GameLaunch_IncludesDistributionPlatform()
         public void Init_LowercasesDistributionPlatform_WhenCallerPassesMixedCase()
         {
             var config = MakeConfig();
-            config.DistributionPlatform = "Steam";
+            config.DistributionPlatform = TestFixtures.DistributionPlatformSteamCased;
             ImmutableAudience.Init(config);
 
             Assert.AreEqual(DistributionPlatforms.Steam, config.DistributionPlatform,
@@ -1135,7 +1135,7 @@ public void Init_LowercasesDistributionPlatform_WhenCallerPassesMixedCase()
         public void Init_LowercasesDistributionPlatform_WhenCallerPassesAllUpperCase()
         {
             var config = MakeConfig();
-            config.DistributionPlatform = "STEAM";
+            config.DistributionPlatform = TestFixtures.DistributionPlatformSteamUppercase;
             ImmutableAudience.Init(config);
 
             Assert.AreEqual(DistributionPlatforms.Steam, config.DistributionPlatform);
@@ -1199,7 +1199,7 @@ public void Init_GameLaunch_IncludesLaunchContextProviderFields()
         {
             ImmutableAudience.LaunchContextProvider = () => new Dictionary<string, object>
             {
-                [GameLaunchPropertyKeys.Platform] = "WindowsPlayer",
+                [GameLaunchPropertyKeys.Platform] = TestFixtures.PlatformWindows,
                 [GameLaunchPropertyKeys.Version] = "1.2.3",
                 [GameLaunchPropertyKeys.BuildGuid] = "a1b2c3d4e5f6",
                 [GameLaunchPropertyKeys.UnityVersion] = "2022.3.20f1",
@@ -1224,7 +1224,7 @@ public void Init_GameLaunch_ConfigDistributionPlatformOverridesProvider()
         {
             ImmutableAudience.LaunchContextProvider = () => new Dictionary<string, object>
             {
-                [GameLaunchPropertyKeys.DistributionPlatform] = "provider_value",
+                [GameLaunchPropertyKeys.DistributionPlatform] = TestFixtures.ProviderValue,
             };
 
             var config = MakeConfig();
@@ -1237,7 +1237,7 @@ public void Init_GameLaunch_ConfigDistributionPlatformOverridesProvider()
                 .Select(File.ReadAllText)
                 .First(c => c.Contains($"\"{EventNames.GameLaunch}\""));
             StringAssert.Contains($"\"{GameLaunchPropertyKeys.DistributionPlatform}\":\"{DistributionPlatforms.Steam}\"", launchFile);
-            Assert.IsFalse(launchFile.Contains("provider_value"),
+            Assert.IsFalse(launchFile.Contains(TestFixtures.ProviderValue),
                 "config.DistributionPlatform should win over the provider's value");
         }
 
@@ -1325,8 +1325,8 @@ public void FullToAnonymous_StripsUserIdFromQueuedTrackAndDropsIdentifyAlias()
         {
             ImmutableAudience.Init(MakeConfig(ConsentLevel.Full));
 
-            ImmutableAudience.Identify("player_steam", IdentityType.Steam);
-            ImmutableAudience.Alias("player_steam", IdentityType.Steam, "player_passport", IdentityType.Passport);
+            ImmutableAudience.Identify(TestFixtures.PlayerSteamId, IdentityType.Steam);
+            ImmutableAudience.Alias(TestFixtures.PlayerSteamId, IdentityType.Steam, TestFixtures.PlayerPassportId, IdentityType.Passport);
             ImmutableAudience.Track(TestEventNames.TrackedBeforeDowngrade);
 
             ImmutableAudience.FlushQueueToDiskForTesting();
@@ -1351,7 +1351,7 @@ public void FullToAnonymous_StripsUserIdFromQueuedTrackAndDropsIdentifyAlias()
         public void FullToAnonymous_FutureTracksOmitUserId()
         {
             ImmutableAudience.Init(MakeConfig(ConsentLevel.Full));
-            ImmutableAudience.Identify("player_steam", IdentityType.Steam);
+            ImmutableAudience.Identify(TestFixtures.PlayerSteamId, IdentityType.Steam);
             ImmutableAudience.SetConsent(ConsentLevel.Anonymous);
 
             ImmutableAudience.Track(TestEventNames.TrackedAfterDowngrade);
diff --git a/src/Packages/Audience/Tests/Runtime/OfflineResilienceTests.cs b/src/Packages/Audience/Tests/Runtime/OfflineResilienceTests.cs
index 7da31a416..341835b80 100644
--- a/src/Packages/Audience/Tests/Runtime/OfflineResilienceTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/OfflineResilienceTests.cs
@@ -64,7 +64,7 @@ private void BlockDiskWrites()
                 foreach (var f in Directory.GetFiles(queueDir, AudiencePaths.QueueGlob)) File.Delete(f);
                 Directory.Delete(queueDir);
             }
-            File.WriteAllText(queueDir, "blocker");
+            File.WriteAllText(queueDir, TestFixtures.DiskBlockerContent);
         }
 
         // -----------------------------------------------------------------
@@ -79,7 +79,7 @@ public void Track_DiskWritesBlocked_DoesNotThrowToCallers()
 
             Assert.DoesNotThrow(() =>
             {
-                for (int i = 0; i < 50; i++) ImmutableAudience.Track($"blocked_{i}");
+                for (int i = 0; i < 50; i++) ImmutableAudience.Track($"{TestEventNames.BlockedPrefix}{i}");
                 ImmutableAudience.FlushQueueToDiskForTesting();
             }, "Track must not propagate disk-write IOException to callers");
 
@@ -95,7 +95,7 @@ public void Shutdown_DiskWritesBlocked_DoesNotThrow()
             ImmutableAudience.Init(MakeConfig());
             ImmutableAudience.Track(TestEventNames.EventPreBlock);
             BlockDiskWrites();
-            for (int i = 0; i < 20; i++) ImmutableAudience.Track($"blocked_{i}");
+            for (int i = 0; i < 20; i++) ImmutableAudience.Track($"{TestEventNames.BlockedPrefix}{i}");
 
             Assert.DoesNotThrow(() => ImmutableAudience.Shutdown(),
                 "Shutdown must absorb disk-write failure during the final drain");
@@ -114,7 +114,7 @@ public void Track_DiskWritesBlocked_RetainsEventsInMemory_AndSurfacesOnError()
             BlockDiskWrites();
 
             const int eventCount = 50;
-            for (int i = 0; i < eventCount; i++) ImmutableAudience.Track($"blocked_{i}");
+            for (int i = 0; i < eventCount; i++) ImmutableAudience.Track($"{TestEventNames.BlockedPrefix}{i}");
             ImmutableAudience.FlushQueueToDiskForTesting();
 
             Assert.GreaterOrEqual(ImmutableAudience.QueueSize, eventCount,
diff --git a/src/Packages/Audience/Tests/Runtime/TestEventNames.cs b/src/Packages/Audience/Tests/Runtime/TestEventNames.cs
index 657c18926..c54a8d7cb 100644
--- a/src/Packages/Audience/Tests/Runtime/TestEventNames.cs
+++ b/src/Packages/Audience/Tests/Runtime/TestEventNames.cs
@@ -26,5 +26,20 @@ internal static class TestEventNames
         internal const string MixedLoadTrack = "mixed_load_track";
         internal const string SteadyState = "steady_state";
         internal const string LevelComplete = "level_complete";
+
+        // EventQueue scenario names where the event name is meaningful in the test description.
+        internal const string IntervalFlush = "interval_flush";
+        internal const string DisposeTest = "dispose_test";
+
+        // Placeholder event names for tests where the event name itself is irrelevant.
+        internal const string PlaceholderA = "a";
+        internal const string PlaceholderB = "b";
+        internal const string PlaceholderTest = "test";
+        internal const string PlaceholderTrack = "track";
+        internal const string PlaceholderIgnored = "ignored";
+        internal const string PlaceholderEvt = "evt";
+
+        // Prefix for OfflineResilienceTests' $"blocked_{i}" loop.
+        internal const string BlockedPrefix = "blocked_";
     }
 }
diff --git a/src/Packages/Audience/Tests/Runtime/TestEventNames.cs.meta b/src/Packages/Audience/Tests/Runtime/TestEventNames.cs.meta
new file mode 100644
index 000000000..5dd577b09
--- /dev/null
+++ b/src/Packages/Audience/Tests/Runtime/TestEventNames.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 0913bc77fd8c4a419bfcdb5dcfebb4e8
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData:
+  assetBundleName:
+  assetBundleVariant:
diff --git a/src/Packages/Audience/Tests/Runtime/TestFixtures.cs b/src/Packages/Audience/Tests/Runtime/TestFixtures.cs
new file mode 100644
index 000000000..dfd7407d3
--- /dev/null
+++ b/src/Packages/Audience/Tests/Runtime/TestFixtures.cs
@@ -0,0 +1,96 @@
+namespace Immutable.Audience.Tests
+{
+    // Per-fixture data values shared across the SDK test suite.
+    internal static class TestFixtures
+    {
+        // Anonymous IDs
+        internal const string AnonId1 = "anon-1";
+        internal const string AnonId42 = "anon-42";
+        internal const string AnonId123 = "anon-123";
+
+        // User IDs
+        internal const string UserId42 = "user-42";
+        internal const string UserId99 = "user-99";
+
+        // Alias endpoints
+        internal const string AliasFromId = "from-id";
+        internal const string AliasToId = "to-id";
+
+        // Identity values keyed to IdentityType.Custom / Steam / Passport
+        internal const string PlayerCustomId = "player-42";
+        internal const string PlayerSteamId = "player_steam";
+        internal const string PlayerPassportId = "player_passport";
+
+        // Resource event payload values
+        internal const string ResourceCurrency = "gold";
+        internal const string ResourceItemType = "quest_reward";
+        internal const string ResourceItemId = "main_quest_01";
+
+        // Purchase event payload values
+        internal const string PurchaseItemId = "gem_pack_01";
+        internal const string PurchaseItemName = "Starter Gem Pack";
+        internal const string PurchaseTransactionId = "txn_abc123";
+
+        // MilestoneReached event payload values
+        internal const string MilestoneName = "first_boss_defeated";
+
+        // Track properties scenario data
+        internal const string CustomPropKeyRecipeId = "recipe_id";
+        internal const string CraftingRecipeIronSword = "iron_sword";
+
+        // Distribution platform fixture for the "platform from outside SDK" path.
+        internal const string ProviderValue = "provider_value";
+
+        // IdentityTypeExtensions.ParseLowercaseString fallback fixture.
+        internal const string UnknownProvider = "unknown_provider";
+
+        // Identity persistence fixtures (id read back from disk on next launch).
+        internal const string PreExistingId = "pre-existing-id";
+        internal const string PreExistingIdFromLastLaunch = "pre-existing-id-from-last-launch";
+
+        // ConsentStore corruption fixture (non-integer file content).
+        internal const string NotAnInt = "not-an-int";
+
+        // ThreadSafetyStressTests userId for race-stress scenarios.
+        internal const string UserRaceStress = "user_race_stress";
+
+        // DeleteDataTests generic userId.
+        internal const string SomeUser = "some-user";
+
+        // Prefix for GzipTests' $"anon-{i}" loop (per-message anonymous IDs).
+        internal const string AnonIdPrefix = "anon-";
+
+        // Placeholders for fixture slots where the value itself is not under test.
+        internal const string GenericUserId = "u1";
+        internal const string GenericFromId = "f";
+        internal const string GenericToId = "t";
+        internal const string GenericFromType = "t1";
+        internal const string GenericToType = "t2";
+
+        // ISO 4217 currency codes used by Purchase / Resource tests.
+        internal const string UsdCurrency = "USD";
+        internal const string EurCurrency = "EUR";
+
+        // Progression.World fixture (used in three typed-event tests).
+        internal const string ProgressionWorldTutorial = "tutorial";
+
+        // Exception message fixture for the ContextProvider sabotage test.
+        internal const string ContextProviderBoomMessage = "boom";
+
+        // File body that occupies the queue directory path so directory creation fails.
+        internal const string DiskBlockerContent = "blocker";
+
+        // DistributionPlatform mixed-case fixtures for Init's lowercase
+        // normalisation test.
+        internal const string DistributionPlatformSteamCased = "Steam";
+        internal const string DistributionPlatformSteamUppercase = "STEAM";
+
+        // Unity Application.platform string for the GameLaunch.Platform test.
+        internal const string PlatformWindows = "WindowsPlayer";
+
+        // Longer generic alias endpoint fixtures, for readability in Alias calls.
+        internal const string GenericAliasFromId = "fromId";
+        internal const string GenericAliasToId = "toId";
+        internal const string GenericAliasFromShort = "from";
+    }
+}
diff --git a/src/Packages/Audience/Tests/Runtime/TestFixtures.cs.meta b/src/Packages/Audience/Tests/Runtime/TestFixtures.cs.meta
new file mode 100644
index 000000000..4376c4879
--- /dev/null
+++ b/src/Packages/Audience/Tests/Runtime/TestFixtures.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: bd6da3a651764490959fa341975848f4
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData:
+  assetBundleName:
+  assetBundleVariant:
diff --git a/src/Packages/Audience/Tests/Runtime/Transport/EventQueueTests.cs b/src/Packages/Audience/Tests/Runtime/Transport/EventQueueTests.cs
index 0a437629c..2661b4dc7 100644
--- a/src/Packages/Audience/Tests/Runtime/Transport/EventQueueTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Transport/EventQueueTests.cs
@@ -35,7 +35,7 @@ public void Enqueue_ThenFlushSync_PersistesEventToDisk()
         {
             using var queue = new EventQueue(_store, flushIntervalSeconds: 60, flushSize: 100);
 
-            queue.Enqueue(Msg("track"));
+            queue.Enqueue(Msg(TestEventNames.PlaceholderTrack));
             queue.FlushSync();
 
             Assert.AreEqual(1, _store.Count(), "event should be on disk after FlushSync");
@@ -77,8 +77,8 @@ public void Shutdown_FlushesRemainingEvents()
         {
             var queue = new EventQueue(_store, flushIntervalSeconds: 60, flushSize: 100);
 
-            queue.Enqueue(Msg("a"));
-            queue.Enqueue(Msg("b"));
+            queue.Enqueue(Msg(TestEventNames.PlaceholderA));
+            queue.Enqueue(Msg(TestEventNames.PlaceholderB));
 
             queue.Shutdown();
 
@@ -99,7 +99,7 @@ public void Enqueue_AfterShutdown_IsIgnored()
             var queue = new EventQueue(_store, flushIntervalSeconds: 60, flushSize: 100);
             queue.Shutdown();
 
-            queue.Enqueue(Msg("ignored"));
+            queue.Enqueue(Msg(TestEventNames.PlaceholderIgnored));
 
             Assert.AreEqual(0, _store.Count(), "events enqueued after Shutdown should be discarded");
         }
@@ -110,7 +110,7 @@ public void IntervalFlush_DrainsToDiskWithoutExplicitCall()
             // Very short interval to make the test fast
             using var queue = new EventQueue(_store, flushIntervalSeconds: 1, flushSize: 100);
 
-            queue.Enqueue(Msg("interval_flush"));
+            queue.Enqueue(Msg(TestEventNames.IntervalFlush));
 
             // Wait slightly longer than the flush interval
             var deadline = DateTime.UtcNow.AddSeconds(4);
@@ -125,7 +125,7 @@ public void Dispose_FlushesAndStopsDrainThread()
         {
             using (var queue = new EventQueue(_store, flushIntervalSeconds: 60, flushSize: 100))
             {
-                queue.Enqueue(Msg("dispose_test"));
+                queue.Enqueue(Msg(TestEventNames.DisposeTest));
             } // Dispose called here
 
             Assert.AreEqual(1, _store.Count(), "Dispose should flush events to disk");
diff --git a/src/Packages/Audience/Tests/Runtime/Transport/HttpTransportTests.cs b/src/Packages/Audience/Tests/Runtime/Transport/HttpTransportTests.cs
index b7f41f040..2c599c723 100644
--- a/src/Packages/Audience/Tests/Runtime/Transport/HttpTransportTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Transport/HttpTransportTests.cs
@@ -17,6 +17,15 @@ namespace Immutable.Audience.Tests
     [TestFixture]
     internal class HttpTransportTests
     {
+        // Response body fixtures.
+        private const string MalformedResponseBody = "not-json";
+        private const string EmptyJsonObjectBody = "{}";
+
+        // Exception messages thrown by MockHandler factories.
+        private const string ConnectionRefusedMessage = "connection refused";
+        private const string RequestTimedOutMessage = "Request timed out";
+        private const string SimulatedCancellationMessage = "simulated";
+
         private string _testDir = null!;
         private DiskStore _store = null!;
 
@@ -49,8 +58,8 @@ public void TearDown()
         [Test]
         public async Task SendBatchAsync_200_DeletesFilesFromDisk()
         {
-            _store.Write(WireFixture.Track((MessageFields.EventName, "a")));
-            _store.Write(WireFixture.Track((MessageFields.EventName, "b")));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderA)));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderB)));
 
             var handler = new MockHandler(HttpStatusCode.OK, $"{{\"accepted\":2,\"{ResponseFields.Rejected}\":0}}");
             using var transport = new HttpTransport(_store, TestDefaults.PublishableKey, handler: handler);
@@ -65,7 +74,7 @@ public async Task SendBatchAsync_200_DeletesFilesFromDisk()
         [Test]
         public async Task SendBatchAsync_200_SendsGzippedPayloadWithCorrectHeaders()
         {
-            _store.Write(WireFixture.Track((MessageFields.EventName, "test")));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderTest)));
 
             byte[]? capturedBody = null;
             string? capturedKey = null;
@@ -97,7 +106,7 @@ public async Task SendBatchAsync_200_SendsGzippedPayloadWithCorrectHeaders()
         [Test]
         public async Task SendBatchAsync_200_SendsPlainJsonPayloadWithoutContentEncoding()
         {
-            _store.Write(WireFixture.Track((MessageFields.EventName, "test")));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderTest)));
 
             string? capturedKey = null;
             string? capturedContentType = null;
@@ -176,7 +185,7 @@ public async Task SendBatchAsync_BaseUrlOverride_WinsOverKeyPrefix()
         [Test]
         public async Task SendBatchAsync_EmptyQueue_ReturnsFalse()
         {
-            var handler = new MockHandler(HttpStatusCode.OK, "{}");
+            var handler = new MockHandler(HttpStatusCode.OK, EmptyJsonObjectBody);
             using var transport = new HttpTransport(_store, TestDefaults.PublishableKey, handler: handler);
 
             var sent = await transport.SendBatchAsync();
@@ -322,8 +331,8 @@ public async Task SendBatchAsync_200_WithRejected_DeletesFilesAndSurfacesValidat
             // per-message validation errors. The batch is deleted (retries
             // would not help) and the count is surfaced via onError so
             // studios can observe silently dropped events.
-            _store.Write(WireFixture.Track((MessageFields.EventName, "a")));
-            _store.Write(WireFixture.Track((MessageFields.EventName, "b")));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderA)));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderB)));
 
             var handler = new MockHandler(HttpStatusCode.OK, $"{{\"accepted\":1,\"{ResponseFields.Rejected}\":1}}");
             AudienceError? reportedError = null;
@@ -341,7 +350,7 @@ public async Task SendBatchAsync_200_WithRejected_DeletesFilesAndSurfacesValidat
         [Test]
         public async Task SendBatchAsync_200_ZeroRejected_DoesNotFireOnError()
         {
-            _store.Write(WireFixture.Track((MessageFields.EventName, "a")));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderA)));
 
             var handler = new MockHandler(HttpStatusCode.OK, $"{{\"accepted\":1,\"{ResponseFields.Rejected}\":0}}");
             AudienceError? reportedError = null;
@@ -357,9 +366,9 @@ public async Task SendBatchAsync_200_ZeroRejected_DoesNotFireOnError()
         public async Task SendBatchAsync_200_MalformedBody_TreatsAsZeroRejected()
         {
             // Malformed diagnostic body must not block the success path.
-            _store.Write(WireFixture.Track((MessageFields.EventName, "a")));
+            _store.Write(WireFixture.Track((MessageFields.EventName, TestEventNames.PlaceholderA)));
 
-            var handler = new MockHandler(HttpStatusCode.OK, "not-json");
+            var handler = new MockHandler(HttpStatusCode.OK, MalformedResponseBody);
             AudienceError? reportedError = null;
             using var transport = new HttpTransport(_store, TestDefaults.PublishableKey,
                 onError: e => reportedError = e, handler: handler);
@@ -491,7 +500,7 @@ public async Task SendBatchAsync_NetworkError_KeepsFilesAndBacksOff()
         {
             _store.Write(WireFixture.Track());
 
-            var handler = new MockHandler(() => throw new HttpRequestException("connection refused"));
+            var handler = new MockHandler(() => throw new HttpRequestException(ConnectionRefusedMessage));
             AudienceError? reportedError = null;
             using var transport = new HttpTransport(_store, TestDefaults.PublishableKey,
                 onError: e => reportedError = e, handler: handler);
@@ -514,7 +523,7 @@ public async Task SendBatchAsync_HttpClientTimeout_TreatedAsNetworkError()
             // NetworkError path.
             _store.Write(WireFixture.Track());
 
-            var handler = new MockHandler(() => throw new TaskCanceledException("Request timed out"));
+            var handler = new MockHandler(() => throw new TaskCanceledException(RequestTimedOutMessage));
             AudienceError? reportedError = null;
             using var transport = new HttpTransport(_store, TestDefaults.PublishableKey,
                 onError: e => reportedError = e, handler: handler);
@@ -540,7 +549,7 @@ public async Task SendBatchAsync_CallerCancelled_Throws_DoesNotDeleteOrRecordFai
             // forever: nothing ever drains, nothing ever throws.
             _store.Write(WireFixture.Track());
 
-            var handler = new MockHandler(() => throw new OperationCanceledException("simulated"));
+            var handler = new MockHandler(() => throw new OperationCanceledException(SimulatedCancellationMessage));
             AudienceError? reportedError = null;
             using var transport = new HttpTransport(_store, TestDefaults.PublishableKey,
                 onError: e => reportedError = e, handler: handler);
diff --git a/src/Packages/Audience/Tests/Runtime/Utility/GzipTests.cs b/src/Packages/Audience/Tests/Runtime/Utility/GzipTests.cs
index efc40110a..995b2f1ba 100644
--- a/src/Packages/Audience/Tests/Runtime/Utility/GzipTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Utility/GzipTests.cs
@@ -35,7 +35,7 @@ public void Compress_OutputIsSmallerThanInput_ForRealisticPayload()
                 if (i > 0) sb.Append(',');
                 sb.Append(WireFixture.Track(
                     (MessageFields.EventName, TestEventNames.LevelComplete),
-                    (MessageFields.AnonymousId, $"anon-{i}")));
+                    (MessageFields.AnonymousId, $"{TestFixtures.AnonIdPrefix}{i}")));
             }
 
             sb.Append("]}");
diff --git a/src/Packages/Audience/Tests/Runtime/Utility/JsonReaderTests.cs b/src/Packages/Audience/Tests/Runtime/Utility/JsonReaderTests.cs
index 36ef4e543..a1e8bb796 100644
--- a/src/Packages/Audience/Tests/Runtime/Utility/JsonReaderTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Utility/JsonReaderTests.cs
@@ -16,15 +16,15 @@ public void EmptyObject()
         [Test]
         public void StringValue()
         {
-            var result = JsonReader.DeserializeObject("{\"key\":\"hello\"}");
-            Assert.AreEqual("hello", result["key"]);
+            var result = JsonReader.DeserializeObject(JsonRoundTripFixtures.KeyHelloEncoded);
+            Assert.AreEqual(JsonRoundTripFixtures.HelloValue, result[JsonRoundTripFixtures.KeyName]);
         }
 
         [Test]
         public void StringWithEscapes()
         {
-            var result = JsonReader.DeserializeObject("{\"val\":\"say \\\"hi\\\"\\nback\\\\slash\\ttab\"}");
-            Assert.AreEqual("say \"hi\"\nback\\slash\ttab", result["val"]);
+            var result = JsonReader.DeserializeObject(JsonRoundTripFixtures.ValEscapeRichEncoded);
+            Assert.AreEqual(JsonRoundTripFixtures.EscapeRichString, result[JsonRoundTripFixtures.ValName]);
         }
 
         [Test]
@@ -47,9 +47,9 @@ public void BoolAndNull()
         [Test]
         public void NestedObject()
         {
-            var result = JsonReader.DeserializeObject("{\"outer\":{\"inner\":\"value\"}}");
-            var inner = (Dictionary<string, object>)result["outer"];
-            Assert.AreEqual("value", inner["inner"]);
+            var result = JsonReader.DeserializeObject(JsonRoundTripFixtures.OuterInnerEncoded);
+            var inner = (Dictionary<string, object>)result[JsonRoundTripFixtures.OuterKey];
+            Assert.AreEqual(JsonRoundTripFixtures.InnerValue, inner[JsonRoundTripFixtures.InnerKey]);
         }
 
         [Test]
diff --git a/src/Packages/Audience/Tests/Runtime/Utility/JsonRoundTripFixtures.cs b/src/Packages/Audience/Tests/Runtime/Utility/JsonRoundTripFixtures.cs
new file mode 100644
index 000000000..a2aba6f5c
--- /dev/null
+++ b/src/Packages/Audience/Tests/Runtime/Utility/JsonRoundTripFixtures.cs
@@ -0,0 +1,24 @@
+namespace Immutable.Audience.Tests
+{
+    // Paired serialise/deserialise fixtures shared between JsonTests and JsonReaderTests.
+    // Each pair pins the round-trip guarantee.
+    internal static class JsonRoundTripFixtures
+    {
+        // Single string key / value pair.
+        internal const string KeyName = "key";
+        internal const string HelloValue = "hello";
+        internal const string KeyHelloEncoded = "{\"key\":\"hello\"}";
+
+        // String containing every escape sequence the codec handles
+        // (escaped quote, newline, backslash, tab).
+        internal const string ValName = "val";
+        internal const string EscapeRichString = "say \"hi\"\nback\\slash\ttab";
+        internal const string ValEscapeRichEncoded = "{\"val\":\"say \\\"hi\\\"\\nback\\\\slash\\ttab\"}";
+
+        // Nested object.
+        internal const string OuterKey = "outer";
+        internal const string InnerKey = "inner";
+        internal const string InnerValue = "value";
+        internal const string OuterInnerEncoded = "{\"outer\":{\"inner\":\"value\"}}";
+    }
+}
diff --git a/src/Packages/Audience/Tests/Runtime/Utility/JsonRoundTripFixtures.cs.meta b/src/Packages/Audience/Tests/Runtime/Utility/JsonRoundTripFixtures.cs.meta
new file mode 100644
index 000000000..3b0ae78e4
--- /dev/null
+++ b/src/Packages/Audience/Tests/Runtime/Utility/JsonRoundTripFixtures.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 0203f7f2c4e64d7f86b9734903dce417
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData:
+  assetBundleName:
+  assetBundleVariant:
diff --git a/src/Packages/Audience/Tests/Runtime/Utility/JsonTests.cs b/src/Packages/Audience/Tests/Runtime/Utility/JsonTests.cs
index b8f9c4524..fcb9d08ce 100644
--- a/src/Packages/Audience/Tests/Runtime/Utility/JsonTests.cs
+++ b/src/Packages/Audience/Tests/Runtime/Utility/JsonTests.cs
@@ -18,11 +18,11 @@ public void Serialize_EmptyDict_ReturnsEmptyObject()
         [Test]
         public void Serialize_StringValue_ReturnsQuotedString()
         {
-            var data = new Dictionary<string, object> { { "key", "hello" } };
+            var data = new Dictionary<string, object> { { JsonRoundTripFixtures.KeyName, JsonRoundTripFixtures.HelloValue } };
 
             var result = Json.Serialize(data);
 
-            Assert.AreEqual("{\"key\":\"hello\"}", result);
+            Assert.AreEqual(JsonRoundTripFixtures.KeyHelloEncoded, result);
         }
 
         [Test]
@@ -30,12 +30,12 @@ public void Serialize_StringWithSpecialChars_EscapesCorrectly()
         {
             var data = new Dictionary<string, object>
             {
-                { "val", "say \"hi\"\nback\\slash\ttab" }
+                { JsonRoundTripFixtures.ValName, JsonRoundTripFixtures.EscapeRichString }
             };
 
             var result = Json.Serialize(data);
 
-            Assert.AreEqual("{\"val\":\"say \\\"hi\\\"\\nback\\\\slash\\ttab\"}", result);
+            Assert.AreEqual(JsonRoundTripFixtures.ValEscapeRichEncoded, result);
         }
 
         [Test]
@@ -84,14 +84,14 @@ public void Serialize_NestedDict_ReturnsNestedObject()
             var data = new Dictionary<string, object>
             {
                 {
-                    "outer", new Dictionary<string, object>
+                    JsonRoundTripFixtures.OuterKey, new Dictionary<string, object>
                     {
-                        { "inner", "value" }
+                        { JsonRoundTripFixtures.InnerKey, JsonRoundTripFixtures.InnerValue }
                     }
                 }
             };
 
-            Assert.AreEqual("{\"outer\":{\"inner\":\"value\"}}", Json.Serialize(data));
+            Assert.AreEqual(JsonRoundTripFixtures.OuterInnerEncoded, Json.Serialize(data));
         }
 
         [Test]
@@ -183,7 +183,7 @@ public void Serialize_RealisticEventPayload_ProducesCorrectJson()
             {
                 { MessageFields.Type, MessageTypes.Track },
                 { MessageFields.EventName, TestEventNames.LevelComplete },
-                { MessageFields.AnonymousId, "anon-123" },
+                { MessageFields.AnonymousId, TestFixtures.AnonId123 },
                 { MessageFields.UserId, null },
                 { MessageFields.Properties, new Dictionary<string, object>
                     {