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Using Convex with Vercel

New to Convex? Convex is the reactive backend-as-a-service for web developers. Convex allows you to define your backend with JavaScript functions that push updates your React components in realtime. To get started, head to the tutorial or the homepage.

Hosting your Convex app on Vercel allows you to automatically re-deploy both your backend and your frontend whenever you push to git.

Deploying to Vercel

If you haven't done so, create a Vercel account. This is free for small projects and should take less than a minute to set up. When asked to deploy a first project just click the link to skip that step for now.

Once you have a working project that runs locally and have created a GitHub repo for it, create a project at https://vercel.com/new and link the project to the source code repository.

Vercel Config

We need to make two changes from the Vercel defaults.

First, go into "Build and Output Settings" and override the "Build Command" to be npx convex deploy && npm run build. We'll discuss why this is necessary in a bit.

Second, let's add a Convex deploy key as an environment variable:

  1. Go to the Convex Dashboard.
  2. Find your project and click "Settings".
  3. Copy the "Deploy key".
  4. In Vercel, click "Environment Variables".
  5. Add an environment variable with the name CONVEX_DEPLOY_KEY and paste the deploy key as the value.

If your Convex project is nested under a subdirectory you'll also need to change "Root Directory" accordingly.

Click the Deploy button and your work here is done!

Vercel will automatically publish your site to an URL like https://<site-name>.vercel.app, shown on the page after deploying. Every time you push a git revision, Vercel will automatically deploy your Convex functions and publish your site changes.

How it works

In Vercel, we overrode the "Build Command" to be npx convex deploy && npm run build.

npx convex deploy will read CONVEX_DEPLOY_KEY from the environment and use that key to push your Convex functions to the production deployment of this Convex project. This deployment has separate data from the dev deployment used in npx convex dev.

Now, Convex has your newest functions and your app is configured to connect to production. Lastly, the npm run build script bundles your app and Vercel deploys it!

tip

If you're using Auth0 for authentication as we outline here, then you'll need to update your Auth0 Application to include your new <site-name>.vercel.app URL in the places where we specified localhost:3000 before. This way Auth0 allows this domain to receive the authentication tokens.