React App Blank Page After Deploy
Your React app works perfectly on localhost. You deploy it, open the URL, and get a blank white page, or the home page loads but every other route returns 404 on refresh. A Codersarts React engineer finds why the production build fails in the browser and gets it rendering.
A React app that shows a blank page after deployment is usually hitting one of four problems: the JavaScript and CSS files aren't loading from the expected path, the server doesn't send app routes back to index.html, a runtime error crashes the whole app in production, or users have a cached index.html that points to files that no longer exist. The browser console and network tab show which one within minutes.
Typical symptoms | White screen, 404 on page refresh, missing JavaScript files, MIME type errors, chunk loading errors |
Most common causes | Wrong base path, missing server rewrites, production-only runtime errors, stale cached files, missing environment variables |
How we fix it | Inspect console and network errors, serve the production build locally, fix paths, routing, and crashes, verify on the live host |
Turnaround | Same-day diagnosis; most fixes in 24–48 hours |
Price | Live Debug from $20; fixed-price quote for the full fix |
Signs Your React Deployment Has This Problem
A blank white page with no visible error
The home page loads, but refreshing any other page returns 404
Console shows Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of text/html
Console shows ChunkLoadError or Failed to fetch dynamically imported module
JavaScript and CSS files return 404 in the network tab
The app works at the root domain but not in a subfolder or on GitHub Pages
An API URL or other setting is undefined only in production
Why React Apps Show a Blank Page in Production
In development, the dev server handles routing, file paths, and errors for you. In production, a static host serves a folder of built files, and anything the dev server was handling becomes your responsibility.
1. Wrong base path
If the app is served from a subfolder, the build must know that path. Otherwise the HTML requests JavaScript from the wrong location. When the server returns an HTML page instead of the missing file, the browser reports a MIME type error and nothing renders.
2. No rewrite for client-side routes
React Router handles routes in the browser. When a user refreshes /dashboard, the server looks for a real file at that path, finds none, and returns 404 unless it's configured to serve index.html for app routes.
3. A runtime error crashes the entire app
An undefined value, missing environment variable, or failed API response can throw an error during rendering. Without an error boundary, React unmounts everything and leaves a blank page.
4. Environment variables missing at build time
Build tools embed environment variables when the app is built, and only variables with the right prefix are exposed to the browser. Variables set only locally, or added to the host after the build, are undefined in production.
5. Stale cached files after a new deploy
Each build creates new file names. If a browser or CDN keeps an old index.html, it requests files deleted by the new deployment and fails with chunk loading errors.
How We Diagnose the Blank Page
Read the browser console. Identify runtime errors, MIME type errors, and chunk loading failures.
Check the network tab. Find which files return 404 or HTML instead of JavaScript.
Serve the production build locally. Run the built files, not the dev server, to reproduce the failure.
Compare paths. Check the build's base path against the URL where the app is actually hosted.
Review host configuration. Confirm rewrite rules for client-side routes and cache settings for index.html.
Check environment variables. Verify each variable has the correct prefix and exists at build time on the host.
How We Fix It
Root cause | Fix |
Wrong base path | Set the correct base path in the build configuration and router for the hosting location |
404 on refresh | Add rewrite rules so app routes serve index.html on Vercel, Netlify, Nginx, S3, or your host |
Runtime crash | Fix the failing code and add error boundaries so one broken component doesn't blank the whole app |
Missing environment variables | Use the required prefix, set variables in the build environment, and rebuild |
Stale cached files | Prevent caching of index.html, cache hashed assets long-term, and handle failed chunk loads gracefully |
We verify the fix on your real hosting setup, including deep links, page refreshes, and a fresh deployment.
Example Fix
Situation: A company's React customer portal, built with Vite and deployed to an S3 and CloudFront setup, showed a blank page for most users after launch.
Cause: The build assumed the app lived at the domain root while it was served from a subfolder, and CloudFront had no rule to return index.html for app routes. Returning users also received a cached index.html from the previous build.
Fix: Set the correct base path for the build and router, added CloudFront error and routing rules for client-side routes, and changed caching so index.html is always revalidated.
Result: The portal loaded for all users, deep links worked, and later deployments stopped causing blank pages.
How to Keep It From Happening Again
Preview the production build - locally before every deployment.
Add error boundaries and error tracking - so production crashes are visible instead of blank.
Configure caching deliberately - with index.html revalidated and hashed files cached.
What You Get
Root cause confirmed and explained
App rendering correctly on your host, including deep links
Error handling added for production crashes
Deployment and caching configuration documented
Frequently Asked Questions
Why is my React app blank after deployment?
Usually the JavaScript files aren't loading from the right path, a runtime error crashes the app, or the server isn't configured for client-side routes. The browser console shows which one.
Why does refreshing a page give 404 in my React app?
The server looks for a file matching that URL. It needs a rewrite rule that serves index.html for app routes so React Router can handle them.
What does the MIME type text/html error mean?
The browser requested a JavaScript file but received an HTML page, usually because the file path is wrong and the server returned index.html or an error page instead.
Why are my environment variables undefined in production?
They're embedded at build time and must use the prefix your build tool requires. Set them in the host's build environment, then rebuild.
How do I fix ChunkLoadError after a new deployment?
Stop caching index.html so browsers get the latest file references, and handle failed chunk loads by prompting a refresh.
Related Problems
Next.js build failing on Vercel
Lovable app not deploying
React state not updating
AWS EC2 app not accessible
CORS error blocking API requests
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