diff --git a/.github/workflows/e2e_with_cache.yaml b/.github/workflows/e2e_with_cache.yaml
deleted file mode 100644
index 7c04221333c..00000000000
--- a/.github/workflows/e2e_with_cache.yaml
+++ /dev/null
@@ -1,54 +0,0 @@
-# This workflow runs system tests: Use the Rector application from the source
-# checkout to process "fixture" projects in e2e/ directory
-# to see if those can be processed successfully
-name: End to End tests with cache
-
-on:
-    pull_request:
-        branches:
-            - main
-    push:
-        branches:
-            - main
-
-env:
-    # see https://github.com/composer/composer/issues/9368#issuecomment-718112361
-    COMPOSER_ROOT_VERSION: "dev-main"
-
-jobs:
-    end_to_end:
-        runs-on: ubuntu-latest
-        timeout-minutes: 3
-        strategy:
-            fail-fast: false
-            matrix:
-                php_version: ['8.4']
-                directory:
-                    - 'e2e/applied-rule-removed-node-with-cache'
-                    - 'e2e/timeout-file-not-cached'
-
-        name: End to end test - ${{ matrix.directory }}
-
-        steps:
-            -   uses: actions/checkout@v5
-
-            -   uses: shivammathur/setup-php@v2
-                with:
-                    php-version: ${{ matrix.php_version }}
-                    coverage: none
-
-            # run in root rector-src
-            -   run: composer install --ansi
-
-            # run in e2e subdir
-            -
-                run: composer install --ansi
-                working-directory: ${{ matrix.directory }}
-
-            # run e2e test
-            -   run: php ../e2eTestRunner.php
-                working-directory: ${{ matrix.directory }}
-
-            # this tests that a 2nd run with cache and "--dry-run" gives same results, see https://github.com/rectorphp/rector-src/pull/3614#issuecomment-1507742338
-            -   run: php ../e2eTestRunnerWithCache.php
-                working-directory: ${{ matrix.directory }}
diff --git a/config/config.php b/config/config.php
index b1afe8533af..db093de4e03 100644
--- a/config/config.php
+++ b/config/config.php
@@ -2,9 +2,7 @@
 
 declare(strict_types=1);
 
-use OndraM\CiDetector\CiDetector;
 use Rector\Bootstrap\ExtensionConfigResolver;
-use Rector\Caching\ValueObject\Storage\MemoryCacheStorage;
 use Rector\Config\RectorConfig;
 
 return static function (RectorConfig $rectorConfig): void {
@@ -27,12 +25,6 @@
     $rectorConfig->cacheDirectory(sys_get_temp_dir() . '/rector_cached_files');
     $rectorConfig->containerCacheDirectory(sys_get_temp_dir());
 
-    // use faster in-memory cache in CI.
-    // CI always starts from scratch, therefore IO intensive caching is not worth it
-    if (new CiDetector()->isCiDetected()) {
-        $rectorConfig->cacheClass(MemoryCacheStorage::class);
-    }
-
     // load internal rector-* extension configs
     $extensionConfigResolver = new ExtensionConfigResolver();
     foreach ($extensionConfigResolver->provide() as $extensionConfigFile) {
diff --git a/e2e/applied-rule-removed-node-with-cache/.gitignore b/e2e/applied-rule-removed-node-with-cache/.gitignore
deleted file mode 100644
index 61ead86667c..00000000000
--- a/e2e/applied-rule-removed-node-with-cache/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-/vendor
diff --git a/e2e/applied-rule-removed-node-with-cache/composer.json b/e2e/applied-rule-removed-node-with-cache/composer.json
deleted file mode 100644
index 5468cd74606..00000000000
--- a/e2e/applied-rule-removed-node-with-cache/composer.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-    "require": {
-        "php": "^8.1"
-    },
-    "minimum-stability": "dev",
-    "prefer-stable": true
-}
diff --git a/e2e/applied-rule-removed-node-with-cache/expected-output.diff b/e2e/applied-rule-removed-node-with-cache/expected-output.diff
deleted file mode 100644
index 94f3ee2fa9d..00000000000
--- a/e2e/applied-rule-removed-node-with-cache/expected-output.diff
+++ /dev/null
@@ -1,40 +0,0 @@
-2 files with changes
-====================
-
-1) src/AlwaysTrue.php:4
-
-    ---------- begin diff ----------
-@@ Line 4 @@
- {
-     public function run()
-     {
--        if (1 === 1) {
--        }
--
-         return 'no';
-     }
- }
-    ----------- end diff -----------
-
-Applied rules:
- * RemoveAlwaysTrueIfConditionRector
-
-
-2) src/DeadConstructor.php:2
-
-    ---------- begin diff ----------
-@@ Line 2 @@
-
- final class DeadConstructor
- {
--    public function __construct()
--    {
--    }
- }
-    ----------- end diff -----------
-
-Applied rules:
- * RemoveEmptyClassMethodRector
-
-
- [OK] 2 files would have been changed (dry-run) by Rector
diff --git a/e2e/applied-rule-removed-node-with-cache/rector.php b/e2e/applied-rule-removed-node-with-cache/rector.php
deleted file mode 100644
index 84cdd17281d..00000000000
--- a/e2e/applied-rule-removed-node-with-cache/rector.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-use Rector\Caching\ValueObject\Storage\FileCacheStorage;
-use Rector\Config\RectorConfig;
-use Rector\DeadCode\Rector\ClassMethod\RemoveEmptyClassMethodRector;
-use Rector\DeadCode\Rector\If_\RemoveAlwaysTrueIfConditionRector;
-
-return static function (RectorConfig $rectorConfig): void {
-    $rectorConfig->cacheClass(FileCacheStorage::class);
-
-    $rectorConfig->paths([
-        __DIR__ . '/src',
-    ]);
-
-    $rectorConfig->rule(RemoveEmptyClassMethodRector::class);
-    $rectorConfig->rule(RemoveAlwaysTrueIfConditionRector::class);
-};
diff --git a/e2e/applied-rule-removed-node-with-cache/src/AlwaysTrue.php b/e2e/applied-rule-removed-node-with-cache/src/AlwaysTrue.php
deleted file mode 100644
index 7b70b9e9ccd..00000000000
--- a/e2e/applied-rule-removed-node-with-cache/src/AlwaysTrue.php
+++ /dev/null
@@ -1,12 +0,0 @@
-<?php
-
-final class AlwaysTrue
-{
-    public function run()
-    {
-        if (1 === 1) {
-        }
-
-        return 'no';
-    }
-}
diff --git a/e2e/applied-rule-removed-node-with-cache/src/DeadConstructor.php b/e2e/applied-rule-removed-node-with-cache/src/DeadConstructor.php
deleted file mode 100644
index 03d800c4879..00000000000
--- a/e2e/applied-rule-removed-node-with-cache/src/DeadConstructor.php
+++ /dev/null
@@ -1,8 +0,0 @@
-<?php
-
-final class DeadConstructor
-{
-    public function __construct()
-    {
-    }
-}
diff --git a/e2e/e2eTestRunnerWithCache.php b/e2e/e2eTestRunnerWithCache.php
deleted file mode 100644
index 033b7fd2440..00000000000
--- a/e2e/e2eTestRunnerWithCache.php
+++ /dev/null
@@ -1,49 +0,0 @@
-#!/usr/bin/env php
-<?php
-
-// runs a rector e2e test.
-// checks whether we expect a certain output, or alternatively that rector just processed everything without errors
-
-use Rector\Console\Formatter\ColorConsoleDiffFormatter;
-use Rector\Console\Formatter\ConsoleDiffer;
-use Rector\Console\Style\SymfonyStyleFactory;
-use Rector\Differ\DefaultDiffer;
-use Rector\Util\Reflection\PrivatesAccessor;
-use Symfony\Component\Console\Command\Command;
-
-$projectRoot = __DIR__ .'/..';
-$rectorBin = $projectRoot . '/bin/rector';
-$autoloadFile = $projectRoot . '/vendor/autoload.php';
-
-// so we can use helper classes here
-require_once __DIR__ . '/../vendor/autoload.php';
-
-$e2eCommand = 'php '. $rectorBin .' process --dry-run --no-ansi -a '. $autoloadFile;
-
-exec($e2eCommand, $output, $exitCode);
-$output = trim(implode("\n", $output));
-$output = str_replace(__DIR__, '.', $output);
-
-$expectedDiff = 'expected-output.diff';
-if (!file_exists($expectedDiff)) {
-    echo $output;
-    exit($exitCode);
-}
-
-$symfonyStyleFactory = new SymfonyStyleFactory(new PrivatesAccessor());
-$symfonyStyle =  $symfonyStyleFactory->create();
-
-$matchedExpectedOutput = false;
-$expectedOutput = trim((string) file_get_contents($expectedDiff));
-if ($output === $expectedOutput) {
-    $symfonyStyle->success('End-to-end test successfully completed');
-    exit(Command::SUCCESS);
-}
-
-// print color diff, to make easy find the differences
-$defaultDiffer = new DefaultDiffer();
-$colorConsoleDiffFormatter = new ColorConsoleDiffFormatter();
-$diff = $colorConsoleDiffFormatter->format($defaultDiffer->diff($output, $expectedOutput));
-$symfonyStyle->writeln($diff);
-
-exit(Command::FAILURE);
diff --git a/e2e/timeout-file-not-cached/.gitignore b/e2e/timeout-file-not-cached/.gitignore
deleted file mode 100644
index 61ead86667c..00000000000
--- a/e2e/timeout-file-not-cached/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-/vendor
diff --git a/e2e/timeout-file-not-cached/composer.json b/e2e/timeout-file-not-cached/composer.json
deleted file mode 100644
index 5468cd74606..00000000000
--- a/e2e/timeout-file-not-cached/composer.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-    "require": {
-        "php": "^8.1"
-    },
-    "minimum-stability": "dev",
-    "prefer-stable": true
-}
diff --git a/e2e/timeout-file-not-cached/expected-output.diff b/e2e/timeout-file-not-cached/expected-output.diff
deleted file mode 100644
index 26cd1063c43..00000000000
--- a/e2e/timeout-file-not-cached/expected-output.diff
+++ /dev/null
@@ -1,7 +0,0 @@
-[ERROR] Could not process
-         "/home/runner/work/rector-src/rector-src/vendor/symplify/easy-parallel/
-         src/ValueObject/ParallelProcess.php" file, due to:
-         "Child process timed out after 0 seconds". On line: 105
-
- [ERROR] Could not process some files, due to:
-         "Reached system errors count limit of 50, exiting...".
diff --git a/e2e/timeout-file-not-cached/rector.php b/e2e/timeout-file-not-cached/rector.php
deleted file mode 100644
index b6053d61914..00000000000
--- a/e2e/timeout-file-not-cached/rector.php
+++ /dev/null
@@ -1,18 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-use Rector\Caching\ValueObject\Storage\FileCacheStorage;
-use Rector\Config\RectorConfig;
-use Rector\Set\ValueObject\LevelSetList;
-
-return static function (RectorConfig $rectorConfig): void {
-    $rectorConfig->cacheClass(FileCacheStorage::class);
-    $rectorConfig->parallel(0);
-
-    $rectorConfig->paths([
-        __DIR__ . '/src',
-    ]);
-
-    $rectorConfig->sets([LevelSetList::UP_TO_PHP_82]);
-};
diff --git a/e2e/timeout-file-not-cached/src/SomeFixturePrinter.php b/e2e/timeout-file-not-cached/src/SomeFixturePrinter.php
deleted file mode 100644
index 69ed3a47227..00000000000
--- a/e2e/timeout-file-not-cached/src/SomeFixturePrinter.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-class SomeFixturePrinter
-{
-    public function run($a, $b)
-    {
-        return strpos($a, $b);
-    }
-}
\ No newline at end of file
diff --git a/phpstan.neon b/phpstan.neon
index 5e74f14907b..ed4572029f8 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -46,7 +46,6 @@ parameters:
         - rules-tests
         - utils
         - scripts
-        - e2e/e2eTestRunnerWithCache.php
         - e2e/e2eTestRunner.php
 
     scanDirectories:
diff --git a/src/Caching/CacheFactory.php b/src/Caching/CacheFactory.php
index 5277e982734..61d2dfd0dc4 100644
--- a/src/Caching/CacheFactory.php
+++ b/src/Caching/CacheFactory.php
@@ -4,6 +4,7 @@
 
 namespace Rector\Caching;
 
+use OndraM\CiDetector\CiDetector;
 use Rector\Caching\ValueObject\Storage\FileCacheStorage;
 use Rector\Caching\ValueObject\Storage\MemoryCacheStorage;
 use Rector\Configuration\Option;
@@ -22,24 +23,20 @@ public function __construct(
      */
     public function create(): Cache
     {
-        $cacheDirectory = SimpleParameterProvider::provideStringParameter(Option::CACHE_DIR);
-
-        $cacheClass = FileCacheStorage::class;
-
-        if (SimpleParameterProvider::hasParameter(Option::CACHE_CLASS)) {
-            $cacheClass = SimpleParameterProvider::provideStringParameter(Option::CACHE_CLASS);
+        // in CI the workspace is ephemeral and usually starts from scratch,
+        // so a file cache that is never read again is only wasted IO → use faster in-memory cache
+        if (new CiDetector()->isCiDetected()) {
+            return new Cache(new MemoryCacheStorage());
         }
 
-        if ($cacheClass === FileCacheStorage::class) {
-            // ensure cache directory exists
-            if (! $this->fileSystem->exists($cacheDirectory)) {
-                $this->fileSystem->mkdir($cacheDirectory);
-            }
+        $cacheDirectory = SimpleParameterProvider::provideStringParameter(Option::CACHE_DIR);
 
-            $fileCacheStorage = new FileCacheStorage($cacheDirectory, $this->fileSystem);
-            return new Cache($fileCacheStorage);
+        // ensure cache directory exists
+        if (! $this->fileSystem->exists($cacheDirectory)) {
+            $this->fileSystem->mkdir($cacheDirectory);
         }
 
-        return new Cache(new MemoryCacheStorage());
+        $fileCacheStorage = new FileCacheStorage($cacheDirectory, $this->fileSystem);
+        return new Cache($fileCacheStorage);
     }
 }
diff --git a/src/Config/RectorConfig.php b/src/Config/RectorConfig.php
index 1f4581bb286..ef492c30300 100644
--- a/src/Config/RectorConfig.php
+++ b/src/Config/RectorConfig.php
@@ -431,11 +431,14 @@ public function containerCacheDirectory(string $directoryPath): void
     /**
      * @param class-string<CacheStorageInterface> $cacheClass
      */
+    #[Deprecated(message: <<<'TXT'
+    Cache storage is selected automatically: file cache locally, in-memory cache in CI,
+     where the ephemeral workspace makes writing a cache that is never re-read wasted IO.
+     The passed value is ignored.
+    TXT)]
     public function cacheClass(string $cacheClass): void
     {
         Assert::isAOf($cacheClass, CacheStorageInterface::class);
-
-        SimpleParameterProvider::setParameter(Option::CACHE_CLASS, $cacheClass);
     }
 
     /**
diff --git a/src/Configuration/Option.php b/src/Configuration/Option.php
index 6c3ddb126fe..e5fd0c98457 100644
--- a/src/Configuration/Option.php
+++ b/src/Configuration/Option.php
@@ -4,9 +4,6 @@
 
 namespace Rector\Configuration;
 
-use Rector\Caching\Contract\ValueObject\Storage\CacheStorageInterface;
-use Rector\Caching\ValueObject\Storage\FileCacheStorage;
-
 final class Option
 {
     public const string SOURCE = 'source';
@@ -145,15 +142,6 @@ final class Option
      */
     public const string CACHE_DIR = 'cache_dir';
 
-    /**
-     * Cache backend. Most of the time we cache in files, but in ephemeral environment (e.g. CI), a faster `MemoryCacheStorage` can be useful.
-     * @internal Use RectorConfig::cacheClass() instead
-     *
-     * @var class-string<CacheStorageInterface>
-     * @internal
-     */
-    public const string CACHE_CLASS = FileCacheStorage::class;
-
     public const string DEBUG = 'debug';
 
     public const string XDEBUG = 'xdebug';
diff --git a/src/Configuration/RectorConfigBuilder.php b/src/Configuration/RectorConfigBuilder.php
index 97411cb1c03..cb62b024e18 100644
--- a/src/Configuration/RectorConfigBuilder.php
+++ b/src/Configuration/RectorConfigBuilder.php
@@ -103,11 +103,6 @@ final class RectorConfigBuilder
      */
     private array $fileExtensions = [];
 
-    /**
-     * @var null|class-string<CacheStorageInterface>
-     */
-    private ?string $cacheClass = null;
-
     private ?string $cacheDirectory = null;
 
     private ?string $containerCacheDirectory = null;
@@ -314,10 +309,6 @@ public function __invoke(RectorConfig $rectorConfig): void
             $rectorConfig->fileExtensions($this->fileExtensions);
         }
 
-        if ($this->cacheClass !== null) {
-            $rectorConfig->cacheClass($this->cacheClass);
-        }
-
         if ($this->cacheDirectory !== null) {
             $rectorConfig->cacheDirectory($this->cacheDirectory);
         }
@@ -830,6 +821,9 @@ public function withFileExtensions(array $fileExtensions): self
     }
 
     /**
+     * The $cacheClass argument is deprecated and ignored. Cache storage is selected automatically:
+     * file cache locally, in-memory cache in CI.
+     *
      * @param class-string<CacheStorageInterface>|null $cacheClass
      */
     public function withCache(
@@ -838,7 +832,6 @@ public function withCache(
         ?string $containerCacheDirectory = null
     ): self {
         $this->cacheDirectory = $cacheDirectory;
-        $this->cacheClass = $cacheClass;
         $this->containerCacheDirectory = $containerCacheDirectory;
 
         return $this;
diff --git a/tests/Caching/Detector/config.php b/tests/Caching/Detector/config.php
index 5e535c343a8..5e5a9c61284 100644
--- a/tests/Caching/Detector/config.php
+++ b/tests/Caching/Detector/config.php
@@ -2,10 +2,8 @@
 
 declare(strict_types=1);
 
-use Rector\Caching\ValueObject\Storage\MemoryCacheStorage;
 use Rector\Config\RectorConfig;
 
 return static function (RectorConfig $rectorConfig): void {
     $rectorConfig->cacheDirectory(sys_get_temp_dir() . '/_rector_cached_files_test');
-    $rectorConfig->cacheClass(MemoryCacheStorage::class);
 };
diff --git a/tests/Caching/ValueObject/Storage/config.php b/tests/Caching/ValueObject/Storage/config.php
index 5e535c343a8..5e5a9c61284 100644
--- a/tests/Caching/ValueObject/Storage/config.php
+++ b/tests/Caching/ValueObject/Storage/config.php
@@ -2,10 +2,8 @@
 
 declare(strict_types=1);
 
-use Rector\Caching\ValueObject\Storage\MemoryCacheStorage;
 use Rector\Config\RectorConfig;
 
 return static function (RectorConfig $rectorConfig): void {
     $rectorConfig->cacheDirectory(sys_get_temp_dir() . '/_rector_cached_files_test');
-    $rectorConfig->cacheClass(MemoryCacheStorage::class);
 };