The site doesn't look right

Blank white page after deploying

The browser tab shows your site's title, but the page is empty: no error, nothing on screen.

Checked 16 October 2026

The short answer

Open the browser console (F12). A 404 on a .js file means the base path is wrong. A red JavaScript error usually means something your computer has, like an environment variable, is missing on the host.

Find your cause

5 causes, most likely first

  1. 1

    The script files give 404

    How to tell: The Console or Network tab shows a 404 for a file like /assets/index-a1b2c3.js.

    Fix

    The build points at the wrong folder. On a GitHub Pages project site, set the base path; elsewhere, check that the host publishes your build folder.

  2. 2

    Environment variables are missing

    How to tell: The console shows an error about something undefined, such as an API address or key.

    Fix

    Your .env file isn't uploaded. Add the variables in the host's settings and deploy again: they're written into the files at build time, so a redeploy is needed.

    In Vite, only variables starting with VITE_ reach the browser. Anything that reaches the browser is public, so never put a secret key there.

  3. 3

    The router doesn't know the subfolder

    How to tell: On a GitHub Pages project site the app loads, but shows nothing at /REPO/.

    Fix

    Give the router the same base as the build, for example <BrowserRouter basename="/REPO"> in React Router.

  4. 4

    A JavaScript error in the production build

    How to tell: The console shows an error in red that you don't see with npm run dev.

    Fix

    Build and preview the production version on your computer (npm run build, then npx vite preview or npx serve dist) to get the same error where you can debug it.

  5. 5

    You opened index.html by double-clicking it

    How to tell: It's blank on your own computer, at a file:// address.

    Fix

    Built apps load their scripts as modules from absolute paths, which browsers block on file://. Preview through a local server, or put it online.

Questions

Also asked

How do I open the console?

Press F12 (or Cmd+Option+I on a Mac) and choose the Console tab. Reload the page with it open so you see every message.

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