StackBlitz Not Working in Firefox or Safari

How to fix it

Try these in order — the most common fix is first.

1. 1. Open the preview in a separate window

   Copy steps
   1. In Firefox or Safari, open the server preview in its own window instead of the frame
   2. Reload if assets were blocked
   Did this fix it? Yes No

2. 2. Leave Private Browsing in Firefox

   Copy steps
   1. Open a normal Firefox window
   2. Reopen the project; web servers cannot run in Private windows
   Did this fix it? Yes No

3. 3. Update Safari or switch browser

   Copy steps
   1. Use Safari 16.4 or later on macOS or iOS 16.4+
   2. If it still fails, use Chrome or another Chromium browser
   Did this fix it? Yes No

Symptoms

Server previews fail, third-party assets are blocked, or no web server starts in Firefox or Safari.

Why it happens

• Firefox and Safari are beta platforms
• Firefox Private Browsing disallows Service Workers
• Safari before 16.4 lacks required APIs like Atomics.waitAsync
• credentialless mode only exists in Chromium

This guide also covers

• stackblitz firefox not working
• stackblitz safari
• webcontainers browser support

Other StackBlitz errors

• StackBlitz Unable to Run Embedded Project: Third-Party Cookies Blocked
• StackBlitz Stuck on "Running start command" in Brave
• StackBlitz Out of Memory on Mobile or Large Projects
• StackBlitz "Cannot load native addon because loading addons is disabled"
• StackBlitz npm ERR! code ERESOLVE Conflicting Peer Dependency
• StackBlitz Preview Reloading in an Infinite Loop
• Bolt.new Preview Blank Screen or "Your Preview Will Appear Here"
• Bolt.new Tokens Running Out Too Fast