API Proxying

Often you’ll be developing your Lustre application alongside a separate backend app. This can cause some problems during development as you’ll typically run into CORS issues when your Lustre app tries to make requests to your backend running on a different port.

To solve this, Lustre’s development server includes support for proxying API requests to another server. This means your application code doesn’t require environment-specific logic to determine where to send API requests to, instead it always hits a path like /api/users and the development server takes care of proxying that request to your backend.

Configuration

To configure the API proxy, you’ll need to add an entry to your gleam.toml file under the tools.lustre.dev section. The most common configuration looks something like this:

[tools.lustre.dev]
proxy = { from = "/api", to = "http://localhost:3000/api" }

In this example, any requests made to paths starting with /api will be forwarded to http://localhost:3000/api. So a request to /api/users would be proxied to http://localhost:3000/api/users.