rift-node

The official Node.js / TypeScript SDK, published as @rift-vs/rift. ESM only, requires Node 20+, and the core package has zero runtime dependencies.

Install 

npm install --save-dev @rift-vs/rift

@rift-vs/rift covers the connect and spawn transports. The in-process engine behind rift.embedded() lives in a second package — installing it is what opts your project into koffi as a dependency:

npm install --save-dev @rift-vs/rift-embedded

Hello world 

import { rift, imposter, onGet, onPost, okJson, created, status, times } from '@rift-vs/rift';

await using engine = await rift.embedded(); // or rift.connect(url) / rift.spawn()

const users = await engine.create(
  imposter('users')
    .record()
    .stub(onGet('/api/users/1').willReturn(okJson({ id: 1, name: 'Alice' })))
    .stub(onPost('/api/users').willReturn(created().latency(50), status(503)))); // cycling

// point your system under test at users.url, then:
await users.verify(onGet('/api/users/1'), times(1));

Coming from Mountebank

The Mountebank-compatible create() surface is permanent, not a transitional shim:

import rift from '@rift-vs/rift';

const server = await rift.create({ port: 2525 });
// ... create imposters, run your tests ...
await server.close();

Raw Mountebank imposter JSON round-trips through fromJson() and can be mixed with DSL-built imposters on the same engine, so the typed DSL can be adopted one stub at a time. See also the Node.js integration guide on this site.

Further reading