Web UI fails to load - JS module blocked due to incorrect MIME type #6122

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1. nathabonfim59

   added

   bugSomething isn't workingSomething isn't working

   on Dec 24, 2025
2. github-actions

   assigned

   adamdotdevin

   on Dec 24, 2025
3. github-actions

   added

   webRelates to opencode on web / desktopRelates to opencode on web / desktop

   on Dec 24, 2025
4. github-actions commented on Dec 24, 2025

   

   github-actionsBot

   on Dec 24, 2025 – with GitHub Actions

   Contributor

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   This issue might be a duplicate of existing issues. Please check:

   • opencode web mode broken: empty page - multiple versions and multiple os #5237: opencode web mode broken: empty page - multiple versions and multiple os (same MIME type error when assets fail to load)
   • Web/desktop breaks with blank page #6109: Web/desktop breaks with blank page (similar blank page issue reported in recent versions)

   Feel free to ignore if none of these address your specific case.
5. nathabonfim59 commented on Dec 24, 2025

   

   nathabonfim59

   on Dec 24, 2025

   Author

   More actions

   It seems to work in when running with bun dev from source
6. nathabonfim59 commented on Dec 25, 2025

   

   nathabonfim59

   on Dec 25, 2025

   Author

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   It appears to be fixed in 1.0.200. Thanks!
7. nathabonfim59

   closed this as completedon Dec 25, 2025
8. mrsaraiva commented on Dec 26, 2025

   

   mrsaraiva

   on Dec 26, 2025

   Last edited by mrsaraiva

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   Still broken on 1.0.203 (CORS errors), launched with "opencode web --hostname 0.0.0.0 --port 4096":

   

   Note that this issue occurs when I attempt to access the web UI from a different machine. The CORS errors are gone if I access from the same machine (regardless of whether I use "localhost", "127.0.0.1" or the actual LAN IP).
9. mrsaraiva commented on Dec 26, 2025

   

   mrsaraiva

   on Dec 26, 2025

   Last edited by mrsaraiva

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   Just FYI, if anyone else is running into this, the workaround is to load the web UI using:

   http://lan_ip:port/?url=http://lan_ip:port

   For a permanent fix, here's a patch that can be applied to packages/app/src/app.tsx and makes it respect whatever was passed to "--hostname"

     --- a/packages/app/src/app.tsx
     +++ b/packages/app/src/app.tsx
     @@ -34,6 +34,12 @@ const url = iife(() => {
   
        if (location.hostname.includes("opencode.ai")) return "http://localhost:4096"
        if (window.__OPENCODE__) return `http://127.0.0.1:${window.__OPENCODE__.port}`
     +
     +  // If accessing from a non-localhost hostname (e.g., LAN IP via --hostname),
     +  // use the current origin since the API is served from the same server
     +  if (!["localhost", "127.0.0.1"].includes(location.hostname)) {
     +    return window.location.origin
     +  }
     +
        if (import.meta.env.DEV)
          return `http://${import.meta.env.VITE_OPENCODE_SERVER_HOST ?? "localhost"}:${import.meta.env.VITE_OPENCODE_SERVER_PORT ?? "4096"}`