diff --git a/frontend/package.json b/frontend/package.json
index 66aa4f9..297625e 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -7,7 +7,7 @@
         "dev": "vite --host 0.0.0.0",
         "build": "vue-tsc -b && vite build",
         "preview": "vite preview",
-        "postinstall": "node patches/patch-exiftool-stderr.mjs"
+        "postinstall": "node patches/patch-exiftool-stderr.mjs && node patches/patch-zeroperl-worker-fetch.mjs"
     },
     "dependencies": {
         "@tailwindcss/vite": "^4.3.3",
diff --git a/frontend/patches/README.md b/frontend/patches/README.md
index dee9429..1965824 100644
--- a/frontend/patches/README.md
+++ b/frontend/patches/README.md
@@ -14,3 +14,16 @@ Instead, `patches/patch-exiftool-stderr.mjs` runs on `postinstall` and removes t
 See the script for exact literals and upstream context.
 
 When upgrading `@uswriting/exiftool`, run `npm install` and confirm the script still finds both guards (or update the script for the new bundle).
+
+## `@6over3/zeroperl-ts@1.0.10` — WASM load in module workers
+
+`patches/patch-zeroperl-worker-fetch.mjs` changes the WASM loader so a custom `fetch` (from `@uswriting/exiftool` options) is honored even when `document` is missing (Web Workers).
+
+| Snippet | Role |
+| ----- | ---- |
+| `if(Ee())a=await...` → `if(Ee()\|\|e)a=await...` (ESM) | Use fetch path when `options.fetch` is set |
+| `if(pe())a=await...` → `if(pe()\|\|e)a=await...` (CJS) | Same for CJS bundle |
+
+Workers still pass Vite’s WASM URL via `zeroperl.wasm?url` and `exiftoolParseOptions.fetch` in app code.
+
+When upgrading `@6over3/zeroperl-ts`, re-run `npm install` and confirm the script still matches (or update literals).
diff --git a/frontend/patches/patch-zeroperl-worker-fetch.mjs b/frontend/patches/patch-zeroperl-worker-fetch.mjs
new file mode 100644
index 0000000..9a2dc72
--- /dev/null
+++ b/frontend/patches/patch-zeroperl-worker-fetch.mjs
@@ -0,0 +1,60 @@
+/**
+ * Patch @6over3/zeroperl-ts@1.0.10 after install.
+ *
+ * Problem: WASM loader treats only `window` + `document` as browser. Module workers have
+ * neither, so it dynamic-imports `node:fs/promises` and fails under Vite.
+ * Custom `fetch` from @uswriting/exiftool is ignored on that branch.
+ *
+ * Fix: use the fetch path when a custom fetch is provided (`Ee() || e`).
+ *
+ * Upstream: https://github.com/6over3/zeroperl-ts
+ *
+ * Re-verify when bumping @6over3/zeroperl-ts: search dist for the ORIGINAL snippets below.
+ */
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const patches = [
+    {
+        relativePath: 'esm/index.js',
+        original: 'if(Ee())a=await(await(e??fetch)(q)).arrayBuffer();',
+        patched: 'if(Ee()||e)a=await(await(e??fetch)(q)).arrayBuffer();'
+    },
+    {
+        relativePath: 'cjs/index.cjs',
+        original: 'if(pe())a=await(await(e??fetch)(w)).arrayBuffer();',
+        patched: 'if(pe()||e)a=await(await(e??fetch)(w)).arrayBuffer();'
+    }
+];
+
+const packageRoot = path.resolve(
+    path.dirname(fileURLToPath(import.meta.url)),
+    '../node_modules/@6over3/zeroperl-ts/dist'
+);
+
+const patchFile = ({ relativePath, original, patched }) => {
+    const filePath = path.join(packageRoot, relativePath);
+
+    if (!fs.existsSync(filePath)) {
+        throw new Error(`patch-zeroperl-worker-fetch: missing ${filePath} (is @6over3/zeroperl-ts installed?)`);
+    }
+
+    const content = fs.readFileSync(filePath, 'utf8');
+
+    if (content.includes(patched)) {
+        return;
+    }
+
+    if (!content.includes(original)) {
+        throw new Error(
+            `patch-zeroperl-worker-fetch: ${relativePath} does not match @6over3/zeroperl-ts@1.0.10; update or remove this script`
+        );
+    }
+
+    fs.writeFileSync(filePath, content.replaceAll(original, patched));
+};
+
+for (const entry of patches) {
+    patchFile(entry);
+}
diff --git a/frontend/src/workers/exiftoolWorker.ts b/frontend/src/workers/exiftoolWorker.ts
index ee42806..603a4e3 100644
--- a/frontend/src/workers/exiftoolWorker.ts
+++ b/frontend/src/workers/exiftoolWorker.ts
@@ -1,8 +1,12 @@
+import zeroperlWasmUrl from '@6over3/zeroperl-ts/zeroperl.wasm?url';
 import { parseMetadata } from '@uswriting/exiftool';
 import { EXIFTOOL_WORKER_INIT_JPEG } from '@/consts/exiftoolWorkerInitJpeg';
 import type { ExiftoolWorkerInMessage } from '@/types/workers/exiftoolWorkerInMessage';
 import { resolveErrorMessage } from '@/utils/resolveErrorMessage';
 
+/** Custom fetch function for `@uswriting/exiftool` to load `zeroperl.wasm` from the worker. */
+const exiftoolParseOptions = { fetch: () => fetch(zeroperlWasmUrl) };
+
 let initialized = false;
 let initializeWorkerPromise: Promise<void> | null = null;
 
@@ -19,7 +23,7 @@ let initializeWorkerPromise: Promise<void> | null = null;
  * Concurrent callers (init message, read-metadata, future write) share one in-flight warmup.
  *
  * @throws When warmup `parseMetadata` fails (network, WASM, or ExifTool error).
- * @see Main thread `initialize()` posts `{ type: 'init' }` when idle.
+ * @see Main thread `initializeExiftool()` posts `{ type: 'init' }` when idle.
  */
 const initializeWorker = async (): Promise<void> => {
     if (initialized) {
@@ -29,7 +33,10 @@ const initializeWorker = async (): Promise<void> => {
     if (!initializeWorkerPromise) {
         initializeWorkerPromise = (async () => {
             try {
-                const result = await parseMetadata({ name: 'init.jpg', data: EXIFTOOL_WORKER_INIT_JPEG });
+                const result = await parseMetadata(
+                    { name: 'init.jpg', data: EXIFTOOL_WORKER_INIT_JPEG },
+                    exiftoolParseOptions
+                );
 
                 if (!result.success) {
                     throw new Error(result.error);
@@ -69,7 +76,7 @@ self.addEventListener('message', async (event: MessageEvent<ExiftoolWorkerInMess
         try {
             await initializeWorker();
 
-            const result = await parseMetadata(message.file);
+            const result = await parseMetadata(message.file, exiftoolParseOptions);
 
             if (!result.success) {
                 self.postMessage({ type: 'read-metadata-error', id: message.id, message: result.error });