Fix Not Found Page on Remix.run Deployment in Vercel

instructions.md

How to change from Remix App Server configuration to Vercel configuration

Remix.run version: 1.1.3

1. Make sure that your remix.config.js file looks like this:

/**
 * @type {import('@remix-run/dev/config').AppConfig}
 */
module.exports = {
  appDirectory: 'app',
  assetsBuildDirectory: 'public/build',
  publicPath: '/build/',
  serverBuildDirectory: 'api/_build', // original value 'build'
  devServerPort: 8002,
  ignoredRouteFiles: ['.*'],
}

2. Make sure to add Vercel dependency in your package.json doing:

npm i @remix-run/vercel

3. Create api/index.js at the root directory of your project with the following content:

const { createRequestHandler } = require("@remix-run/vercel");

module.exports = createRequestHandler({
  build: require("./_build")
});

4. Remember to ignore the output directory /api/_build in your .gitignore by adding the following line:

/api/_build

That's all! I hope this helps you out with the issue.