diff --git a/backend/src/lib/sep0001-generator.integration.test.js b/backend/src/lib/sep0001-generator.integration.test.js
new file mode 100644
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+++ b/backend/src/lib/sep0001-generator.integration.test.js
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+import { describe, expect, it, beforeEach, afterEach } from "vitest";
+import { generateStellarToml, validateStellarToml } from "./sep0001-generator.js";
+
+const BASE_MERCHANT = {
+  id: "merchant-integration-001",
+  business_name: "Integration Test Merchant",
+  email: "merchant@integration.example.com",
+  notification_email: "notify@integration.example.com",
+  recipient: "GBUQWP3BOUZX34ULNQG23RQ6F4YUSXHTQSXUSMIQSTBE2BRUY4DQAT2B",
+  branding_config: {
+    homepage: "https://integration.example.com",
+    logo_url: "https://integration.example.com/logo.png",
+  },
+};
+
+// ─── Integration tests ────────────────────────────────────────────────────────
+
+describe("SEP-0001 generator — integration: environment variable handling", () => {
+  const savedEnv = {};
+  const ENV_KEYS = [
+    "STELLAR_NETWORK_PASSPHRASE",
+    "API_BASE_URL",
+    "TRANSFER_SERVER_URL",
+    "FEDERATION_SERVER_URL",
+    "SIGNING_KEY",
+    "DOCS_URL",
+  ];
+
+  beforeEach(() => {
+    ENV_KEYS.forEach((k) => {
+      savedEnv[k] = process.env[k];
+      delete process.env[k];
+    });
+  });
+
+  afterEach(() => {
+    ENV_KEYS.forEach((k) => {
+      if (savedEnv[k] === undefined) {
+        delete process.env[k];
+      } else {
+        process.env[k] = savedEnv[k];
+      }
+    });
+  });
+
+  it("uses TRANSFER_SERVER_URL when set, overriding API_BASE_URL default", () => {
+    process.env.TRANSFER_SERVER_URL = "https://payments.example.com/api";
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain('TRANSFER_SERVER = "https://payments.example.com/api"');
+  });
+
+  it("falls back to API_BASE_URL-derived transfer server when TRANSFER_SERVER_URL is absent", () => {
+    process.env.API_BASE_URL = "https://api.example.com";
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain("https://api.example.com/api");
+  });
+
+  it("includes FEDERATION_SERVER when env var is set", () => {
+    process.env.FEDERATION_SERVER_URL = "https://fed.example.com";
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain('FEDERATION_SERVER = "https://fed.example.com"');
+  });
+
+  it("omits FEDERATION_SERVER when env var is absent", () => {
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).not.toContain("FEDERATION_SERVER");
+  });
+
+  it("includes SIGNING_KEY when env var is set", () => {
+    process.env.SIGNING_KEY = "SCZANGBA5ARYOEX4DYUJC7GPZESCSXOZQIMONZPH5GKIQKP52PCMHHCA";
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain("SIGNING_KEY");
+    expect(toml).toContain("SCZANGBA5ARYOEX4DYUJC7GPZESCSXOZQIMONZPH5GKIQKP52PCMHHCA");
+  });
+
+  it("omits SIGNING_KEY when env var is absent", () => {
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).not.toContain("SIGNING_KEY");
+  });
+
+  it("uses DOCS_URL when set, overriding API_BASE_URL-derived default", () => {
+    process.env.DOCS_URL = "https://docs.example.com/api";
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain('DOCUMENTATION = "https://docs.example.com/api"');
+  });
+
+  it("uses mainnet passphrase when configured", () => {
+    process.env.STELLAR_NETWORK_PASSPHRASE = "Public Global Stellar Network ; September 2015";
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain("Public Global Stellar Network");
+  });
+});
+
+describe("SEP-0001 generator — integration: merchant field combinations", () => {
+  beforeEach(() => {
+    process.env.STELLAR_NETWORK_PASSPHRASE = "Test SDF Network ; September 2015";
+    process.env.API_BASE_URL = "http://localhost:4000";
+  });
+
+  it("generates valid TOML for a minimal merchant (no optional fields)", () => {
+    const minimal = { business_name: "Minimal Merchant" };
+    const toml = generateStellarToml(minimal);
+    expect(validateStellarToml(toml)).toBe(true);
+    expect(toml).toContain("Minimal Merchant");
+    expect(toml).not.toContain("contact");
+    expect(toml).not.toContain("support");
+    expect(toml).not.toContain("ACCOUNTS");
+  });
+
+  it("generates ACCOUNTS list when recipient is provided", () => {
+    const toml = generateStellarToml(BASE_MERCHANT);
+    expect(toml).toContain(
+      `ACCOUNTS = ["GBUQWP3BOUZX34ULNQG23RQ6F4YUSXHTQSXUSMIQSTBE2BRUY4DQAT2B"]`
+    );
+  });
+
+  it("output is valid for all generated merchant variants", () => {
+    const variants = [
+      { business_name: "No Email" },
+      { business_name: "With Email", email: "a@b.com" },
+      { business_name: "Full", email: "a@b.com", notification_email: "n@b.com", recipient: "GCEZWKCA5VLDNRLN3RPRJMRZOX3Z6G5CHCGDUPIU2HRHHZLQQFPSH3BB" },
+      { ...BASE_MERCHANT },
+    ];
+    for (const merchant of variants) {
+      const toml = generateStellarToml(merchant);
+      expect(validateStellarToml(toml)).toBe(true);
+    }
+  });
+
+  it("TOML output preserves section ordering (top-level fields before [ORG])", () => {
+    const toml = generateStellarToml(BASE_MERCHANT);
+    const networkIdx = toml.indexOf("NETWORK_PASSPHRASE");
+    const transferIdx = toml.indexOf("TRANSFER_SERVER");
+    const orgIdx = toml.indexOf("[ORG]");
+    expect(networkIdx).toBeLessThan(transferIdx);
+    expect(transferIdx).toBeLessThan(orgIdx);
+  });
+
+  it("double-quotes are correctly escaped inside business_name", () => {
+    const merchant = { ...BASE_MERCHANT, business_name: 'Acme "Best" Payments' };
+    const toml = generateStellarToml(merchant);
+    expect(toml).toContain('Acme \\"Best\\" Payments');
+    expect(validateStellarToml(toml)).toBe(true);
+  });
+
+  it("backslashes are correctly escaped inside business_name", () => {
+    const merchant = { ...BASE_MERCHANT, business_name: "Acme\\Corp" };
+    const toml = generateStellarToml(merchant);
+    expect(toml).toContain("Acme\\\\Corp");
+  });
+
+  it("newlines are escaped in string fields", () => {
+    const merchant = { ...BASE_MERCHANT, business_name: "Line1\nLine2" };
+    const toml = generateStellarToml(merchant);
+    expect(toml).toContain("Line1\\nLine2");
+    expect(validateStellarToml(toml)).toBe(true);
+  });
+});
+
+// ─── Stress tests ─────────────────────────────────────────────────────────────
+
+describe("SEP-0001 generator — stress: throughput and concurrency", () => {
+  beforeEach(() => {
+    process.env.STELLAR_NETWORK_PASSPHRASE = "Test SDF Network ; September 2015";
+    process.env.API_BASE_URL = "http://localhost:4000";
+  });
+
+  it("generates 1 000 TOMLs sequentially in under 500 ms", () => {
+    const start = Date.now();
+    for (let i = 0; i < 1000; i++) {
+      const merchant = { ...BASE_MERCHANT, id: `merchant-${i}`, business_name: `Merchant ${i}` };
+      const toml = generateStellarToml(merchant);
+      expect(validateStellarToml(toml)).toBe(true);
+    }
+    expect(Date.now() - start).toBeLessThan(500);
+  });
+
+  it("generates 200 TOMLs concurrently without errors", async () => {
+    const results = await Promise.all(
+      Array.from({ length: 200 }, (_, i) =>
+        Promise.resolve(
+          generateStellarToml({ ...BASE_MERCHANT, id: `concurrent-${i}`, business_name: `Merchant ${i}` })
+        )
+      )
+    );
+    expect(results).toHaveLength(200);
+    results.forEach((toml) => expect(validateStellarToml(toml)).toBe(true));
+  });
+
+  it("handles very long string fields without crashing", () => {
+    const longName = "A".repeat(10_000);
+    const merchant = { ...BASE_MERCHANT, business_name: longName };
+    const toml = generateStellarToml(merchant);
+    expect(validateStellarToml(toml)).toBe(true);
+    expect(toml).toContain(longName);
+  });
+
+  it("handles merchants with unicode characters in business_name", () => {
+    const merchants = [
+      { business_name: "支付商户" },
+      { business_name: "Händler GmbH" },
+      { business_name: "商人 & Co." },
+      { business_name: "مؤسسة المدفوعات" },
+    ];
+    for (const merchant of merchants) {
+      const toml = generateStellarToml(merchant);
+      expect(validateStellarToml(toml)).toBe(true);
+    }
+  });
+});