diff --git a/keyserver/src/responders/website-responders.js b/keyserver/src/responders/website-responders.js
--- a/keyserver/src/responders/website-responders.js
+++ b/keyserver/src/responders/website-responders.js
@@ -63,7 +63,12 @@
   }
 }
 
-type AssetInfo = { jsURL: string, fontsURL: string, cssInclude: string };
+type AssetInfo = {
+  +jsURL: string,
+  +fontsURL: string,
+  +cssInclude: string,
+  +olmFilename: string,
+};
 let assetInfo: ?AssetInfo = null;
 async function getAssetInfo() {
   if (assetInfo) {
@@ -75,6 +80,7 @@
       jsURL: 'http://localhost:8080/dev.build.js',
       fontsURL,
       cssInclude: '',
+      olmFilename: '',
     };
     return assetInfo;
   }
@@ -91,6 +97,7 @@
           href="compiled/${assets.browser.css}"
         />
       `,
+      olmFilename: assets[''].wasm,
     };
     return assetInfo;
   } catch {
@@ -316,7 +323,7 @@
     return pushConfig.publicKey;
   })();
 
-  const { jsURL, fontsURL, cssInclude } = await assetInfoPromise;
+  const { jsURL, fontsURL, cssInclude, olmFilename } = await assetInfoPromise;
 
   // prettier-ignore
   res.write(html`
@@ -413,6 +420,7 @@
   res.end(html`
     ;
           var baseURL = "${baseURL}";
+          var olmFilename = "${olmFilename}";
         </script>
         <script src="${jsURL}"></script>
       </body>
diff --git a/web/account/log-in-form.react.js b/web/account/log-in-form.react.js
--- a/web/account/log-in-form.react.js
+++ b/web/account/log-in-form.react.js
@@ -12,6 +12,7 @@
 import SIWELoginForm from './siwe-login-form.react.js';
 import TraditionalLoginForm from './traditional-login-form.react.js';
 import OrBreak from '../components/or-break.react.js';
+import { initOlm } from '../olm/olm-utils.js';
 import {
   setPrimaryIdentityKeys,
   setNotificationIdentityKeys,
@@ -42,7 +43,7 @@
       ) {
         return;
       }
-      await olm.init();
+      await initOlm();
 
       const identityAccount = new olm.Account();
       identityAccount.create();
diff --git a/web/olm/olm-utils.js b/web/olm/olm-utils.js
new file mode 100644
--- /dev/null
+++ b/web/olm/olm-utils.js
@@ -0,0 +1,16 @@
+// @flow
+
+import olm from '@matrix-org/olm';
+
+declare var olmFilename: string;
+
+async function initOlm(): Promise<void> {
+  if (!olmFilename) {
+    return await olm.init();
+  }
+  const locateFile = (wasmFilename: string, httpAssetsHost: string) =>
+    httpAssetsHost + olmFilename;
+  return await olm.init({ locateFile });
+}
+
+export { initOlm };
diff --git a/web/webpack.config.cjs b/web/webpack.config.cjs
--- a/web/webpack.config.cjs
+++ b/web/webpack.config.cjs
@@ -12,16 +12,6 @@
 const babelConfig = require('./babel.config.cjs');
 
 const baseBrowserConfig = {
-  plugins: [
-    new CopyPlugin({
-      patterns: [
-        {
-          from: 'node_modules/@matrix-org/olm/olm.wasm',
-          to: path.join(__dirname, 'dist'),
-        },
-      ],
-    }),
-  ],
   entry: {
     browser: ['./script.js'],
   },
@@ -58,12 +48,30 @@
       directory: path.join(__dirname, 'dist'),
     },
   },
+  plugins: [
+    new CopyPlugin({
+      patterns: [
+        {
+          from: 'node_modules/@matrix-org/olm/olm.wasm',
+          to: path.join(__dirname, 'dist'),
+        },
+      ],
+    }),
+  ],
 };
 
 const baseProdBrowserConfig = {
   ...baseBrowserConfig,
   plugins: [
-    ...baseBrowserConfig.plugins,
+    new CopyPlugin({
+      patterns: [
+        {
+          from: 'node_modules/@matrix-org/olm/olm.wasm',
+          to: path.join(__dirname, 'dist', 'olm.[contenthash:12].wasm'),
+          info: { chunk: 'test' },
+        },
+      ],
+    }),
     new AssetsPlugin({
       filename: 'assets.json',
       path: path.join(__dirname, 'dist'),