Deploying Full-Stack React + Express.js: Debug Failure Error

Juls95 · 2025-02-07 04:40:46.598794+00

I have a full-stack application with: * Frontend: React + Vite * Backend: Express.js server with LangChain and Warden Protocol integration * Structure: Both frontend and backend in same directory (examples/typescript/cli-agent/) The application works locally with: * Frontend on localhost:5173 * Backend API on localhost:3001 Current Configuration: ``` // vercel.json { "version": 2, "builds": [ { "src": "src/server/server.ts", "use": "@vercel/node" }, { "src": "package.json", "use": "@vercel/static-build", "config": { "distDir": "dist", "buildCommand": "npm run build" } } ], "routes": [ { "src": "/api/(.*)", "dest": "/src/server/server.ts" }, { "handle": "filesystem" }, { "src": "/(.*)", "dest": "/index.html" } ] } ``` Issue: When deploying to Vercel, I get: 1. Error: Debug Failure during deployment * Project settings error suggesting to remove .vercel directory Questions: * What's causing the Debug Failure error? * How should I properly configure Vercel for a full-stack application with both frontend and serverless functions? * Is there a better way to structure this for Vercel deployment? Any insights would be appreciated!

I have a full-stack application with:

Frontend: React + Vite
Backend: Express.js server with LangChain and Warden Protocol integration
Structure: Both frontend and backend in same directory (examples/typescript/cli-agent/)

The application works locally with:

Frontend on localhost:5173
Backend API on localhost:3001

Current Configuration:

12// vercel.json34{56"version": 2,78"builds": [910{1112"src": "src/server/server.ts",1314"use": "@vercel/node"1516},1718{1920"src": "package.json",2122"use": "@vercel/static-build",2324"config": {2526"distDir": "dist",2728"buildCommand": "npm run build"2930}3132}3334],3536"routes": [3738{3940"src": "/api/(.*)",4142"dest": "/src/server/server.ts"4344},4546{4748"handle": "filesystem"4950},5152{5354"src": "/(.*)",5556"dest": "/index.html"5758}5960]6162}

Issue:

When deploying to Vercel, I get:

Error: Debug Failure during deployment

Project settings error suggesting to remove .vercel directory

Questions:

What's causing the Debug Failure error?
How should I properly configure Vercel for a full-stack application with both frontend and serverless functions?
Is there a better way to structure this for Vercel deployment?

Any insights would be appreciated!

If you're having trouble deploying an Express app, this guide can help.

https://vercel.com/guides/using-express-with-vercel

You can also ask v0 for suggestions tailored to your own project setup.

Hi , welcome to the Vercel Community!

Thanks for reaching out in the community.

After reading your questions, I can highly recommend the following community post because it shares the recommendations when building a full-stack application on Vercel as well as the caveats and troubleshooting guide.

https://community.vercel.com/t/express-101-everything-about-deploying-your-express-app-on-vercel/4870

Feel free to drop more questions if you have after reading the post.