JavaScript SDK

Packages

Package	Framework
`@ratelane/express`	Express
`@ratelane/fastify`	Fastify

Config options

Both packages share the same config shape:

Option	Type	Required	Description
`apiKey`	`string`	✅	Your Ratelane API key from the dashboard
`collectorUrl`	`string`	✅	`https://api.ratelane.dev` for production
`instanceVersion`	`string`	❌	Your app version, shown in instance detail

Express — attach()

For Express, you must call attach() after all routes are registered. This is how Ratelane discovers your routes:

app.use(ratelane);

// register all your routes here...

ratelane.attach(app); // call last

Fastify — plugin registration

For Fastify, register the plugin before starting the server:

await app.register(ratelaneMiddleware, { ... });
await app.listen({ port: 3000 });

Route discovery

Routes are collected automatically on startup. HEAD routes are filtered from discovery but still enforced normally.

Device info

Every telemetry poll includes:

{
  sdk_version: string,      // auto from package.json
  runtime: 'node',
  runtime_version: string,  // e.g. "20.11.0"
  framework: string,        // e.g. "express"
  instance_version: string  // from your config
}