AI Studio Build Preview stays blank even though the full-stack app is verified healthy

Google AI Studio
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AI Studio Build Preview stays blank even though the full-stack app is verified healthy

I’m a first-time developer building a full-stack React/Vite + Express application in Google AI Studio Build.

I’m posting because I’ve spent a substantial amount of time troubleshooting a completely blank/stalled Build Preview, and I’ve now independently verified that the application itself is healthy.

Update: The application server, Vite module graph, API, React rendering, and container ingress have all been tested successfully. The failure appears to occur only in the embedded AI Studio Preview.

What I’ve verified

The application uses:

  • React 19

  • Vite 6.4.3

  • Node/Express

  • Tailwind CSS v4

The development server starts successfully and reports:

[Deisis Server] Running on http://0.0.0.0:3000 (isDevServer: true)

The process is listening on:

0.0.0.0:3000

The production build also succeeds:

vite v6.4.3 building for production
1797 modules transformed
built in 11.03s
server.ts bundle to dist/server.cjs

HTTP/runtime testing

I tested the running application directly.

These all return HTTP 200:

  • /

  • /api/health

  • /src/main.tsx

  • /@vite/client

  • /@react-refresh

  • /src/App.tsx

  • /src/index.css

I also crawled the complete frontend dependency/module graph.

Result:

  • 82 unique URLs

  • 82/82 returned HTTP 200

  • 0 failed requests

  • 0 404s

  • 0 500s

React rendering

This was not just a static server test.

The React application was actually executed and rendered successfully.

Results:

  • No uncaught React/component exceptions

  • RENDER_SUCCESS

  • #root is populated

  • The rendered DOM is approximately 600 KB

  • The actual application UI/navigation renders successfully

Container/proxy testing

The container ingress was also tested.

Nginx is listening on port 8080 and proxying to localhost:3000.

Requests through the container ingress also return HTTP 200, including the application HTML and Vite/module resources.

Where the problem appears to be

The remaining failure appears to be specifically in the AI Studio embedded Preview iframe/authentication layer.

The diagnostic showed that the preview deployment can load successfully when opened directly in a normal browser tab, while the same application remains blank/stalled when embedded inside the AI Studio Web Studio Preview.

The outer Preview URL goes through an AI Studio authentication bridge and cross-site iframe context, including cookie/authentication handling.

I also adjusted Chrome’s third-party-cookie/site-data settings for the relevant domains, but the embedded Preview remains blank.

Important conclusion

At this point I have stopped making application-code changes because the evidence indicates that the application itself is working correctly.

This is now reproducible as:

Application server healthy + complete module graph healthy + React rendering successfully + embedded AI Studio Preview still blank

I’m trying to determine whether this is:

  • a known AI Studio Build Preview bug,

  • an authentication/cookie problem in the embedded Preview iframe,

  • a Preview synchronization/cache problem,

  • or another AI Studio infrastructure issue.

Has anyone else encountered this exact combination recently?

And, more importantly, is Google currently tracking this issue or is there a known workaround?

I’m a first-time developer, and one of the reasons I chose AI Studio was because I wanted an integrated environment that would let me focus on building the application rather than becoming an expert in development infrastructure.

I’ve learned a lot troubleshooting this, but it has been frustrating to spend so much time modifying and testing application code when the application itself now appears to be demonstrably healthy.

Any guidance from the AI Studio team would be greatly appreciated.