diff --git a/src/engine/runtime.js b/src/engine/runtime.js
index 87b44d0d3..2c5f8eef2 100644
--- a/src/engine/runtime.js
+++ b/src/engine/runtime.js
@@ -18,6 +18,7 @@ const StageLayering = require('./stage-layering');
 const Variable = require('./variable');
 const xmlEscape = require('../util/xml-escape');
 const ScratchLinkWebSocket = require('../util/scratch-link-websocket');
+const fetchWithTimeout = require('../util/fetch-with-timeout');
 
 // Virtual I/O devices.
 const Clock = require('../io/clock');
@@ -1627,6 +1628,7 @@ class Runtime extends EventEmitter {
      */
     attachStorage (storage) {
         this.storage = storage;
+        fetchWithTimeout.setFetch(storage.scratchFetch.scratchFetch);
         this.resetRunId();
     }
 
diff --git a/src/extensions/scratch3_text2speech/index.js b/src/extensions/scratch3_text2speech/index.js
index f45c7010b..8c76a6a11 100644
--- a/src/extensions/scratch3_text2speech/index.js
+++ b/src/extensions/scratch3_text2speech/index.js
@@ -7,7 +7,7 @@ const Cast = require('../../util/cast');
 const MathUtil = require('../../util/math-util');
 const Clone = require('../../util/clone');
 const log = require('../../util/log');
-const fetchWithTimeout = require('../../util/fetch-with-timeout');
+const {fetchWithTimeout} = require('../../util/fetch-with-timeout');
 
 /**
  * Icon svg to be displayed in the blocks category menu, encoded as a data URI.
diff --git a/src/extensions/scratch3_translate/index.js b/src/extensions/scratch3_translate/index.js
index 871ca326a..3964711fc 100644
--- a/src/extensions/scratch3_translate/index.js
+++ b/src/extensions/scratch3_translate/index.js
@@ -2,7 +2,7 @@ const ArgumentType = require('../../extension-support/argument-type');
 const BlockType = require('../../extension-support/block-type');
 const Cast = require('../../util/cast');
 const log = require('../../util/log');
-const fetchWithTimeout = require('../../util/fetch-with-timeout');
+const {fetchWithTimeout} = require('../../util/fetch-with-timeout');
 const languageNames = require('scratch-translate-extension-languages');
 const formatMessage = require('format-message');
 
diff --git a/src/util/fetch-with-timeout.js b/src/util/fetch-with-timeout.js
index 80c1b11f0..465ce1444 100644
--- a/src/util/fetch-with-timeout.js
+++ b/src/util/fetch-with-timeout.js
@@ -1,4 +1,24 @@
-const {scratchFetch} = require('scratch-storage/src/scratchFetch.js');
+/**
+ * @callback FetchFunction
+ * @param {RequestInfo|URL} input
+ * @param {RequestInit|undefined} [init]
+ * @returns {Promise<Response>}
+ */
+
+/**
+ * @type {FetchFunction}
+ */
+let myFetch = global.fetch;
+
+/**
+ * Tell `fetchWithTimeout` to use a specific `fetch` function.
+ * By default, `fetchWithTimeout` will use the global `fetch` function.
+ * If there is no global `fetch`, then `fetchWithTimeout` will fail unless provided with an alternative.
+ * @param {FetchFunction} newFetch The new `fetch` function to use within fetchWithTimeout.
+ */
+const setFetch = newFetch => {
+    myFetch = newFetch;
+};
 
 /**
  * Fetch a remote resource like `fetch` does, but with a time limit.
@@ -14,7 +34,7 @@ const fetchWithTimeout = (resource, init, timeout) => {
     const signal = controller ? controller.signal : null;
     // The fetch call races a timer.
     return Promise.race([
-        scratchFetch(resource, Object.assign({signal}, init)).then(response => {
+        myFetch(resource, Object.assign({signal}, init)).then(response => {
             clearTimeout(timeoutID);
             return response;
         }),
@@ -27,4 +47,7 @@ const fetchWithTimeout = (resource, init, timeout) => {
     ]);
 };
 
-module.exports = fetchWithTimeout;
+module.exports = {
+    fetchWithTimeout,
+    setFetch
+};