StackBlitz Unable to Run Embedded Project: Third-Party Cookies Blocked
Workaround available Chrome, Chromium browsers Updated November 14, 2026Based on 2 user reportsHow we research
Quick answer
WebContainers need browser storage and service workers that blocked third-party cookies break. Enable storage partitioning or add cookie exceptions for the StackBlitz domains in Chrome.
Most likely fix: Enable storage partitioning in Chrome (preferred)
How to fix it
Try these in order — the most common fix is first.
1. Enable storage partitioning in Chrome (preferred)
- Go to chrome://flags/#third-party-storage-partitioning
- Choose Enabled in the dropdown (Default may also work in recent versions)
- Relaunch Chrome and reopen the project
Did this fix it?2. Add cookie exceptions
- Go to chrome://settings/cookies
- Under "Sites that can always use cookies" add https://[*.]stackblitz.io, https://[*.]webcontainer.io and https://[*.]webcontainer-api.io
- Reload the project
Did this fix it?3. Allow cookies for one project
- Click the lock icon in the address bar, then Cookies
- Select the blocked domain and click Allow
- Reload when prompted; repeat if the project domain changes later
Did this fix it?
Symptoms
The project hangs on boot or will not run; the preview never loads, often in Chrome with third-party cookies blocked or in an embedded project.
Why it happens
- Third-party cookies blocked in Chrome preferences
- Brave Shields blocking cross-site cookies
- Project domains change between sessions
This guide also covers
- stackblitz unable to run embedded project
- webcontainers third party cookies
- stackblitz not loading chrome
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