diff --git a/Gruntfile.js b/Gruntfile.js
index c354249f8b69..eba38704f3ee 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -24,9 +24,9 @@ module.exports = function (grunt) {
         cmd: 'node',
         args: ['tools/gen_version'],
       },
-      'generate-listings': {
+      'generate-listings-and-webworkers': {
         cmd: 'node',
-        args: ['tools/gen_listings', 'gen/', ...kAllSuites.map(s => 'src/' + s)],
+        args: ['tools/gen_listings_and_webworkers', 'gen/', ...kAllSuites.map(s => 'src/' + s)],
       },
       validate: {
         cmd: 'node',
@@ -159,14 +159,14 @@ module.exports = function (grunt) {
         // Must run after generate-common and run:build-out.
         files: [
           { expand: true, dest: 'out/', cwd: 'gen', src: 'common/internal/version.js' },
-          { expand: true, dest: 'out/', cwd: 'gen', src: '*/listing.js' },
+          { expand: true, dest: 'out/', cwd: 'gen', src: '*/**/*.js' },
         ],
       },
       'gen-to-out-wpt': {
         // Must run after generate-common and run:build-out-wpt.
         files: [
           { expand: true, dest: 'out-wpt/', cwd: 'gen', src: 'common/internal/version.js' },
-          { expand: true, dest: 'out-wpt/', cwd: 'gen', src: 'webgpu/listing.js' },
+          { expand: true, dest: 'out-wpt/', cwd: 'gen', src: 'webgpu/**/*.js' },
         ],
       },
       'htmlfiles-to-out': {
@@ -243,7 +243,7 @@ module.exports = function (grunt) {
 
   grunt.registerTask('generate-common', 'Generate files into gen/ and src/', [
     'run:generate-version',
-    'run:generate-listings',
+    'run:generate-listings-and-webworkers',
     'run:generate-cache',
   ]);
   grunt.registerTask('build-standalone', 'Build out/ (no checks; run after generate-common)', [
diff --git a/src/common/tools/gen_listings_and_webworkers.ts b/src/common/tools/gen_listings_and_webworkers.ts
new file mode 100644
index 000000000000..ca1f9ff99049
--- /dev/null
+++ b/src/common/tools/gen_listings_and_webworkers.ts
@@ -0,0 +1,91 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import * as process from 'process';
+
+import { crawl } from './crawl.js';
+
+function usage(rc: number): void {
+  console.error(`Usage: tools/gen_listings [options] [OUT_DIR] [SUITE_DIRS...]
+
+For each suite in SUITE_DIRS, generate listings into OUT_DIR/{suite}/listing.js,
+and generate Web Worker proxies in OUT_DIR/{suite}/webworker/**/*.worker.js for
+every .spec.js file. (Note {suite}/webworker/ is reserved for this purpose.)
+
+Example:
+  tools/gen_listings gen/ src/unittests/ src/webgpu/
+
+Options:
+  --help          Print this message and exit.
+`);
+  process.exit(rc);
+}
+
+const argv = process.argv;
+if (argv.indexOf('--help') !== -1) {
+  usage(0);
+}
+
+{
+  // Ignore old argument that is now the default
+  const i = argv.indexOf('--no-validate');
+  if (i !== -1) {
+    argv.splice(i, 1);
+  }
+}
+
+if (argv.length < 4) {
+  usage(0);
+}
+
+const myself = 'src/common/tools/gen_listings.ts';
+
+const outDir = argv[2];
+
+for (const suiteDir of argv.slice(3)) {
+  // Run concurrently for each suite (might be a tiny bit more efficient)
+  void crawl(suiteDir, false).then(listing => {
+    const suite = path.basename(suiteDir);
+
+    // Write listing.js
+    const outFile = path.normalize(path.join(outDir, `${suite}/listing.js`));
+    fs.mkdirSync(path.join(outDir, suite), { recursive: true });
+    fs.writeFileSync(
+      outFile,
+      `\
+// AUTO-GENERATED - DO NOT EDIT. See ${myself}.
+
+export const listing = ${JSON.stringify(listing, undefined, 2)};
+`
+    );
+
+    // Write suite/webworker/**/*.worker.js
+    for (const entry of listing) {
+      if ('readme' in entry) continue;
+
+      const outFileDir = path.join(
+        outDir,
+        suite,
+        'webworker',
+        ...entry.file.slice(0, entry.file.length - 1)
+      );
+      const outFile = path.join(outDir, suite, 'webworker', ...entry.file) + '.worker.js';
+
+      const relPathToSuiteRoot = Array<string>(entry.file.length).fill('..').join('/');
+
+      fs.mkdirSync(outFileDir, { recursive: true });
+      fs.writeFileSync(
+        outFile,
+        `\
+// AUTO-GENERATED - DO NOT EDIT. See ${myself}.
+
+// oldG is a TestGroup<Fixture> object (defined in common/internal/test_group.ts).
+import { g as oldG } from '${relPathToSuiteRoot}/${entry.file.join('/')}.spec.js';
+
+// FIXME: Expose a proxied test interface. I think this can completely replace test_worker-worker.js
+// (using this instead of that), but if not then hopefully it can at least share code with it.
+console.log(oldG.iterate());
+`
+      );
+    }
+  });
+}
diff --git a/src/demo/webworker/.gitignore b/src/demo/webworker/.gitignore
new file mode 100644
index 000000000000..8496277ad72e
--- /dev/null
+++ b/src/demo/webworker/.gitignore
@@ -0,0 +1,2 @@
+# DIRECTORY RESERVED FOR GENERATED FILES. See gen_listings_and_webworkers.
+*
diff --git a/src/manual/webworker/.gitignore b/src/manual/webworker/.gitignore
new file mode 100644
index 000000000000..8496277ad72e
--- /dev/null
+++ b/src/manual/webworker/.gitignore
@@ -0,0 +1,2 @@
+# DIRECTORY RESERVED FOR GENERATED FILES. See gen_listings_and_webworkers.
+*
diff --git a/src/stress/webworker/.gitignore b/src/stress/webworker/.gitignore
new file mode 100644
index 000000000000..8496277ad72e
--- /dev/null
+++ b/src/stress/webworker/.gitignore
@@ -0,0 +1,2 @@
+# DIRECTORY RESERVED FOR GENERATED FILES. See gen_listings_and_webworkers.
+*
diff --git a/src/unittests/webworker/.gitignore b/src/unittests/webworker/.gitignore
new file mode 100644
index 000000000000..8496277ad72e
--- /dev/null
+++ b/src/unittests/webworker/.gitignore
@@ -0,0 +1,2 @@
+# DIRECTORY RESERVED FOR GENERATED FILES. See gen_listings_and_webworkers.
+*
diff --git a/src/webgpu/webworker/.gitignore b/src/webgpu/webworker/.gitignore
new file mode 100644
index 000000000000..8496277ad72e
--- /dev/null
+++ b/src/webgpu/webworker/.gitignore
@@ -0,0 +1,2 @@
+# DIRECTORY RESERVED FOR GENERATED FILES. See gen_listings_and_webworkers.
+*
diff --git a/tools/gen_listings b/tools/gen_listings
deleted file mode 100755
index 6c25622423a1..000000000000
--- a/tools/gen_listings
+++ /dev/null
@@ -1,7 +0,0 @@
-#!/usr/bin/env node
-
-// Crawl a suite directory (e.g. src/webgpu/) to generate a listing.js containing
-// the listing of test files in the suite.
-
-require('../src/common/tools/setup-ts-in-node.js');
-require('../src/common/tools/gen_listings.ts');
diff --git a/tools/gen_listings_and_webworkers b/tools/gen_listings_and_webworkers
new file mode 100755
index 000000000000..285df3657d2a
--- /dev/null
+++ b/tools/gen_listings_and_webworkers
@@ -0,0 +1,8 @@
+#!/usr/bin/env node
+
+// Crawl a suite directory (e.g. src/webgpu/) to generate a listing.js containing
+// the listing of test files in the suite, and some generated test files
+// (like suite/serviceworker/**/*.spec.js).
+
+require('../src/common/tools/setup-ts-in-node.js');
+require('../src/common/tools/gen_listings_and_webworkers.ts');