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# React Router v7 with middleware fails on Vercel

486 views · 3 likes · 5 posts


V2036 (@vercel-2036) · 2025-10-23 · ♥ 3

### Environment
- **Framework:** React Router v7 (with middleware enabled)
- **Platform:** Vercel
- **Build Status:** ✅ Successful
- **Runtime:** ❌ Function invocation fails with 500 error

### Problem
Deploying a React Router v7 application with middleware to Vercel results in successful builds but runtime failures. The application works locally but fails when deployed.

### Error Message
```
Error: Invalid `context` value provided to `handleRequest`. 
When middleware is enabled you must return an instance of 
`RouterContextProvider` from your `getLoadContext` function.
```

### Full Stack Trace
```
[error] Error: Invalid `context` value provided to `handleRequest`. When middleware is enabled you must return an instance of `RouterContextProvider` from your `getLoadContext` function.
    at Object.requestHandler [as handlerWeb] (/var/task/node_modules/react-router/dist/development/index.js:1153:21)
    at Object.handler (/opt/rust/nodejs.js:2:15439)
    at Server.<anonymous> (/opt/rust/nodejs.js:2:1980)
    at /opt/rust/nodejs.js:16:7828
    at AsyncLocalStorage.run (node:internal/async_local_storage/async_hooks:91:14)
    at /opt/rust/nodejs.js:16:7816
    at AsyncLocalStorage.run (node:internal/async_local_storage/async_hooks:91:14)
    at Server.<anonymous> (/opt/rust/nodejs.js:16:7804)
    at Server.s (/opt/rust/nodejs.js:16:1716)
    at Server.emit (node:events:518:28)
```

### Repository
https://github.com/petervavro/react-router-i18next-example-vercel/tree/main

### Steps to Reproduce
1. Create a React Router v7 from repo (main)
2. Deploy to Vercel
3. Build completes successfully
4. Access any route - function invocation fails with 500 error and there is "Unexpected Server Error" message at the page: https://react-router-i18next-example-vercel-521qac7hs.vercel.app/

### Expected Behavior
The application should run successfully on Vercel, just as it does in local development.

### Additional Context
- Local development works without issues
- The error suggests a mismatch between React Router v7's middleware expectations and Vercel's serverless function adapter
- This appears to be related to how Vercel's build output API handles the `getLoadContext` function with React Router v7 middleware

### Possible Solution
The issue might be related to how Vercel's adapter wraps the React Router handler. React Router v7 with middleware requires `getLoadContext` to return a `RouterContextProvider` instance, but Vercel's runtime might not be handling this correctly.


Csweeney98 (@csweeney98) · 2026-01-05

I’m running into the same error, have you been able to find a solution? I’m thinking of trying to patch packages at this point.


hakobpogh (@hakob-kiraki-dev) · 2026-01-22

I have the same issue… any updates on this?


Julien Deniau (@jdeniau) · 2026-01-31

Same issue here!


Julien Deniau (@jdeniau) · 2026-01-31

Found a working fix in vercel github issues 

https://github.com/vercel/vercel/issues/13327#issuecomment-3387978746

Need to add a server/app.ts file and update vite configuration file to bypass vercel's entry file.