diff --git a/.changeset/heavy-comics-begin.md b/.changeset/heavy-comics-begin.md
new file mode 100644
index 00000000..7d7a7c6b
--- /dev/null
+++ b/.changeset/heavy-comics-begin.md
@@ -0,0 +1,6 @@
+---
+"@fast-check/jest": patch
+"@fast-check/worker": minor
+---
+
+💥(worker) Drop CommonJS support
diff --git a/.github/workflows/build-status.yml b/.github/workflows/build-status.yml
index a8a4772f..4a28936e 100644
--- a/.github/workflows/build-status.yml
+++ b/.github/workflows/build-status.yml
@@ -477,22 +477,22 @@ jobs:
       - name: Switch folder to CommonJS
         run: pnpm --filter {./packages/**} --parallel -c exec "cd test-types && ../../../.github/scripts/rename.sh ts cts"
       - name: Check in CommonJS mode
-        run: pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict *.cts"
+        run: pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --filter '!@fast-check/worker' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict *.cts"
       - name: Check in CommonJS mode with NodeNext
-        run: pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict --module NodeNext --moduleResolution NodeNext *.cts"
+        run: pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --filter '!@fast-check/worker' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict --module NodeNext --moduleResolution NodeNext *.cts"
       - name: Switch folder to ES Modules
         run: pnpm --filter {./packages/**} --parallel -c exec "cd test-types && ../../../.github/scripts/rename.sh cts mts"
       - name: Check in ES Modules mode
         run: |
           if [ "${{ matrix.ts-version }}" = "5.0" ] || [ "${{ matrix.ts-version }}" = "5.7" ]; then
-            pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict *.mts"
+            pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --filter '!@fast-check/worker' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict *.mts"
           else
-            pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict *.mts"
+            pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --filter '!@fast-check/worker' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict *.mts"
           fi
       - name: Check in ES Modules mode with NodeNext
         run: |
           if [ "${{ matrix.ts-version }}" = "5.0" ] || [ "${{ matrix.ts-version }}" = "5.7" ]; then
-            pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict --module NodeNext --moduleResolution NodeNext *.mts"
+            pnpm --filter {./packages/**} --filter '!@fast-check/ava' --filter '!@fast-check/packaged' --filter '!@fast-check/poisoning' --filter '!@fast-check/vitest' --filter '!@fast-check/worker' --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict --module NodeNext --moduleResolution NodeNext *.mts"
           else
             pnpm --filter {./packages/**} --parallel -c exec "cd test-types && pnpm --package typescript@${{ matrix.ts-version }} dlx tsc --noEmit --skipLibCheck --strict --module NodeNext --moduleResolution NodeNext *.mts"
           fi
diff --git a/packages/jest/package.json b/packages/jest/package.json
index 5ceae7f3..e901feab 100644
--- a/packages/jest/package.json
+++ b/packages/jest/package.json
@@ -36,10 +36,10 @@
     "build": "pnpm run build:publish-cjs && pnpm run build:publish-esm && pnpm run build:publish-types",
     "build-ci": "pnpm run build",
     "build:publish-types": "tsc -p tsconfig.publish.types.json && tsc -p tsconfig.publish.types.json --outDir lib/cjs",
-    "build:publish-cjs": "tsc -p tsconfig.publish.json --module commonjs --moduleResolution node10 --outDir lib/cjs && cp package.cjs-template.json lib/cjs/package.json",
+    "build:publish-cjs": "tsc -p tsconfig.publish.json --module commonjs --moduleResolution bundler --outDir lib/cjs && cp package.cjs-template.json lib/cjs/package.json",
     "build:publish-esm": "tsc -p tsconfig.publish.json",
-    "test-bundle:cjs": "node --experimental-vm-modules node_modules/jest/bin/jest.js --config test-bundle/jest.config.cjs",
-    "test-bundle:mjs": "node --experimental-vm-modules node_modules/jest/bin/jest.js --config test-bundle/jest.config.mjs",
+    "test-bundle:cjs": "jest --config test-bundle/cjs/jest.config.cjs",
+    "test-bundle:mjs": "node --experimental-vm-modules node_modules/jest/bin/jest.js --config test-bundle/mjs/jest.config.mjs",
     "test-bundle": "pnpm run test-bundle:cjs && pnpm run test-bundle:mjs",
     "typecheck": "tsc --noEmit"
   },
@@ -71,16 +71,18 @@
     }
   },
   "devDependencies": {
+    "@babel/plugin-transform-modules-commonjs": "^7.22.5",
     "@fast-check/jest": "workspace:*",
     "@fast-check/worker": "workspace:*",
     "@jest/expect": "^30.2.0",
     "@jest/globals": "^30.2.0",
     "@types/jest": "^30.0.0",
     "@types/node": "^24.10.13",
+    "babel-jest": "^30.2.0",
     "fast-check": "workspace:*",
     "jest": "^30.2.0",
     "jest-jasmine2": "^30.2.0",
-    "typescript": "~5.9.3",
+    "typescript": "6.0.0-beta",
     "vite": "^7.3.1",
     "vitest": "^4.0.18"
   },
diff --git a/packages/jest/test-bundle/cjs/babel.config.cjs b/packages/jest/test-bundle/cjs/babel.config.cjs
new file mode 100644
index 00000000..865ee9c5
--- /dev/null
+++ b/packages/jest/test-bundle/cjs/babel.config.cjs
@@ -0,0 +1,3 @@
+module.exports = {
+  presets: [['@babel/preset-env', { targets: { node: 'current' }, modules: 'commonjs' }]],
+};
diff --git a/packages/jest/test-bundle/cjs/jest.config.cjs b/packages/jest/test-bundle/cjs/jest.config.cjs
new file mode 100644
index 00000000..fd592a20
--- /dev/null
+++ b/packages/jest/test-bundle/cjs/jest.config.cjs
@@ -0,0 +1,8 @@
+module.exports = {
+  testMatch: ['<rootDir>/*.spec.cjs'],
+  testTimeout: 20_000,
+  transform: {
+    '^.+\\.[t|j]sx?$': 'babel-jest',
+  },
+  transformIgnorePatterns: ['/node_modules/(?!(?:@fast-check/worker)/)'],
+};
diff --git a/packages/jest/test-bundle/main.spec.cjs b/packages/jest/test-bundle/cjs/main.spec.cjs
similarity index 100%
rename from packages/jest/test-bundle/main.spec.cjs
rename to packages/jest/test-bundle/cjs/main.spec.cjs
diff --git a/packages/jest/test-bundle/worker.spec.cjs b/packages/jest/test-bundle/cjs/worker.spec.cjs
similarity index 100%
rename from packages/jest/test-bundle/worker.spec.cjs
rename to packages/jest/test-bundle/cjs/worker.spec.cjs
diff --git a/packages/jest/test-bundle/jest.config.cjs b/packages/jest/test-bundle/jest.config.cjs
deleted file mode 100644
index 7e7b2459..00000000
--- a/packages/jest/test-bundle/jest.config.cjs
+++ /dev/null
@@ -1,4 +0,0 @@
-module.exports = {
-  testMatch: ['<rootDir>/*.spec.cjs'],
-  testTimeout: 20_000,
-};
diff --git a/packages/jest/test-bundle/jest.config.mjs b/packages/jest/test-bundle/mjs/jest.config.mjs
similarity index 100%
rename from packages/jest/test-bundle/jest.config.mjs
rename to packages/jest/test-bundle/mjs/jest.config.mjs
diff --git a/packages/jest/test-bundle/main.spec.mjs b/packages/jest/test-bundle/mjs/main.spec.mjs
similarity index 100%
rename from packages/jest/test-bundle/main.spec.mjs
rename to packages/jest/test-bundle/mjs/main.spec.mjs
diff --git a/packages/jest/test-bundle/worker.spec.mjs b/packages/jest/test-bundle/mjs/worker.spec.mjs
similarity index 100%
rename from packages/jest/test-bundle/worker.spec.mjs
rename to packages/jest/test-bundle/mjs/worker.spec.mjs
diff --git a/packages/jest/test/jest-fast-check.spec.ts b/packages/jest/test/jest-fast-check.spec.ts
index 6882ea44..7fe3e6fa 100644
--- a/packages/jest/test/jest-fast-check.spec.ts
+++ b/packages/jest/test/jest-fast-check.spec.ts
@@ -601,16 +601,30 @@ async function writeToFile(
 
   // Prepare jest config itself
   const jestConfigPath = path.join(specDirectory, jestConfigName);
+  const jestConfig = {
+    testMatch: [`<rootDir>/${specFileName}`],
+    transform: {},
+    testTimeout: options.testTimeoutConfig,
+    testRunner: options.testRunner !== undefined ? 'jest-jasmine2' : undefined,
+    ...(useWorkers
+      ? {
+          transform: { '^.+\\.[t|j]sx?$': 'babel-jest' },
+          transformIgnorePatterns: ['/node_modules/(?!(?:@fast-check/worker)/)'],
+        }
+      : {}),
+  };
+
+  // Prepare babel config (if needed)
+  const babelConfigPath = path.join(specDirectory, 'babel.config.cjs');
+  const babelConfig = useWorkers
+    ? `module.exports = { presets: [['@babel/preset-env', { targets: { node: 'current' }, modules: 'commonjs' }]], };`
+    : undefined;
 
   // Write the files
   await Promise.all([
     fs.writeFile(specFilePath, specContent),
-    fs.writeFile(
-      jestConfigPath,
-      `module.exports = { testMatch: ['<rootDir>/${specFileName}'], transform: {}, ${
-        options.testTimeoutConfig !== undefined ? `testTimeout: ${options.testTimeoutConfig},` : ''
-      }${options.testRunner !== undefined ? `testRunner: 'jest-jasmine2',` : ''} };`,
-    ),
+    fs.writeFile(jestConfigPath, `module.exports = ${JSON.stringify(jestConfig)};`),
+    ...(babelConfig !== undefined ? [fs.writeFile(babelConfigPath, babelConfig)] : []),
   ]);
 
   return specDirectory;
diff --git a/packages/jest/tsconfig.json b/packages/jest/tsconfig.json
index 51bf44c3..e9135461 100644
--- a/packages/jest/tsconfig.json
+++ b/packages/jest/tsconfig.json
@@ -1,3 +1,6 @@
 {
-  "extends": "../../tsconfig.common.json"
+  "extends": "../../tsconfig.common.json",
+  "compilerOptions": {
+    "types": ["node", "jest"]
+  }
 }
diff --git a/packages/jest/tsconfig.publish.json b/packages/jest/tsconfig.publish.json
index ed67654f..5eab9e4a 100644
--- a/packages/jest/tsconfig.publish.json
+++ b/packages/jest/tsconfig.publish.json
@@ -1,7 +1,9 @@
 {
   "extends": "../../tsconfig.publish.json",
   "compilerOptions": {
-    "outDir": "lib/"
+    "rootDir": "src/",
+    "outDir": "lib/",
+    "types": ["node", "jest"]
   },
   "include": ["src/"]
 }
diff --git a/packages/jest/tsconfig.publish.types.json b/packages/jest/tsconfig.publish.types.json
index e54be824..5a832334 100644
--- a/packages/jest/tsconfig.publish.types.json
+++ b/packages/jest/tsconfig.publish.types.json
@@ -1,7 +1,9 @@
 {
   "extends": "../../tsconfig.publish.types.json",
   "compilerOptions": {
-    "outDir": "lib/"
+    "rootDir": "src/",
+    "outDir": "lib/",
+    "types": ["node", "jest"]
   },
   "include": ["src/"]
 }
diff --git a/packages/worker/package.cjs-template.json b/packages/worker/package.cjs-template.json
deleted file mode 100644
index 5bbefffb..00000000
--- a/packages/worker/package.cjs-template.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "type": "commonjs"
-}
diff --git a/packages/worker/package.json b/packages/worker/package.json
index ac08ffdd..eb4cfaa7 100644
--- a/packages/worker/package.json
+++ b/packages/worker/package.json
@@ -3,31 +3,16 @@
   "description": "Provide built-ins to run predicates directly within dedicated workers",
   "version": "0.5.0",
   "type": "module",
-  "main": "lib/main.js",
   "exports": {
     "./package.json": "./package.json",
-    ".": {
-      "require": {
-        "types": "./lib/cjs/main.d.ts",
-        "default": "./lib/cjs/main.js"
-      },
-      "import": {
-        "types": "./lib/main.d.ts",
-        "default": "./lib/main.js"
-      }
-    }
+    ".": "./lib/main.js"
   },
-  "module": "lib/main.js",
-  "types": "lib/main.d.ts",
   "files": [
     "lib"
   ],
   "scripts": {
-    "build": "pnpm run build:publish-cjs && pnpm run build:publish-esm && pnpm run build:publish-types",
-    "build-ci": "pnpm run build",
-    "build:publish-types": "tsc -p tsconfig.publish.types.json && tsc -p tsconfig.publish.types.json --outDir lib/cjs",
-    "build:publish-cjs": "tsc -p tsconfig.publish.json --module commonjs --moduleResolution node10 --outDir lib/cjs && cp package.cjs-template.json lib/cjs/package.json",
-    "build:publish-esm": "tsc -p tsconfig.publish.json",
+    "build": "rolldown -c",
+    "build-ci": "rolldown -c",
     "test-bundle:cjs": "node test-bundle/main.cjs",
     "test-bundle:mjs": "node test-bundle/main.mjs",
     "test-bundle": "pnpm run test-bundle:cjs && pnpm run test-bundle:mjs",
diff --git a/packages/worker/rolldown.config.js b/packages/worker/rolldown.config.js
new file mode 100644
index 00000000..aa391e22
--- /dev/null
+++ b/packages/worker/rolldown.config.js
@@ -0,0 +1,4 @@
+import buildConfigFor from '../../rolldown.common.config.js';
+import pkg from './package.json' with { type: 'json' };
+
+export default buildConfigFor(pkg, import.meta.dirname);
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 3762f9ef..840b61f4 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -200,6 +200,9 @@ importers:
         specifier: ^3.0.0 || ^4.0.0
         version: link:../fast-check
     devDependencies:
+      '@babel/plugin-transform-modules-commonjs':
+        specifier: ^7.22.5
+        version: 7.28.6(@babel/core@7.29.0)
       '@fast-check/jest':
         specifier: workspace:*
         version: 'link:'
@@ -218,6 +221,9 @@ importers:
       '@types/node':
         specifier: ^24.10.13
         version: 24.10.13
+      babel-jest:
+        specifier: ^30.2.0
+        version: 30.2.0(@babel/core@7.29.0)
       jest:
         specifier: ^30.2.0
         version: 30.2.0(@types/node@24.10.13)
@@ -225,8 +231,8 @@ importers:
         specifier: ^30.2.0
         version: 30.2.0
       typescript:
-        specifier: ~5.9.3
-        version: 5.9.3
+        specifier: 6.0.0-beta
+        version: 6.0.0-beta
       vite:
         specifier: ^7.3.1
         version: 7.3.1(@types/node@24.10.13)(jiti@1.21.7)(lightningcss@1.31.1)(terser@5.46.0)(yaml@2.8.2)
@@ -9674,6 +9680,11 @@ packages:
     engines: {node: '>=14.17'}
     hasBin: true
 
+  typescript@6.0.0-beta:
+    resolution: {integrity: sha512-CldZdztDpQRLM1HC6WDQjQkQN5Ub5zRau737a1diGh3lPmb9oRsaWHk1y5iqK0o7+1bNJ0oXfEGRkAogFZBL+Q==}
+    engines: {node: '>=14.17'}
+    hasBin: true
+
   uc.micro@2.1.0:
     resolution: {integrity: sha512-ARDJmphmdvUk6Glw7y9DQ2bFkKBHwQHLi2lsaH6PPmz/Ka9sFOBsBluozhDltWmnv9u/cF6Rt87znRTPV+yp/A==}
 
@@ -22017,6 +22028,8 @@ snapshots:
 
   typescript@5.9.3: {}
 
+  typescript@6.0.0-beta: {}
+
   uc.micro@2.1.0: {}
 
   ufo@1.6.3: {}