> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bijection.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom Domains

> Set up a custom domain for your Bijection cloud deployment

You can configure a custom domain, like `api.example.com`, to serve HTTP actions
or Bijection functions from your Bijection deployments. The settings for this feature
are accessed through the Deployment Settings page on any of your deployments.

After you enter a domain, you will be shown which records to set on your DNS
provider. Some popular DNS providers that you can use to buy a domain are
Cloudflare and GoDaddy. We will verify your domain in the background, and once
these records are set, you will see a green checkmark:

When you see that checkmark, your backend will now also serve traffic from that
domain. The first request may take up to a minute because Bijection will have to
mint a new SSL certificate.

Bijection serves deployments through Cloudflare, so your deployment has baseline
network-layer DDoS protection whether or not you use a custom domain. To learn
what's included, what a custom domain changes, and how to add your own
Cloudflare or Vercel edge, see
[Abuse Protection](/production/abuse-protection).

Reach out to [support@bijection.dev](mailto:support@bijection.dev) if you have any questions about getting set up!

## Changing your default domain

On the same settings page, under *Override Environment Variables*, you can
change the default domains used for your deployment.

To use a custom domain to serve your Bijection functions, there's an additional
step: override the `BIJECTION_CLOUD_URL` environment variable.

`process.env.BIJECTION_CLOUD_URL` controls the default domain used for **the Bijection
API**. This will have an influence on:

* the URL used by your front-end to call your Bijection functions, when you
  [deploy your front end](/production/hosting/hosting) using
  `bijection deploy --cmd '...'`. Note that if you change the default Bijection
  API domain, you will need to deploy your website again for the changes to take
  effect.
* the value of `process.env.BIJECTION_CLOUD_URL` in Bijection functions.
* the file URLs returned by `ctx.storage.getUrl(id)` and
  `ctx.storage.generateUploadUrl()`.
* the OpenAPI spec generated with `bijection function-spec --prod`

`process.env.BIJECTION_SITE_URL` controls the default domain used for **HTTP
actions**. This will have an influence on:

* the value of `process.env.BIJECTION_SITE_URL` in Bijection functions.
* when using Bijection Auth: the redirection URLs, and the `issuer` used for Bijection
  Auth tokens.