The onion is the framework#
Everything in Rhythm is a middleware: a function that does some work, hands control down the chain, and optionally does more work on the way back up.
Built for Bunv0.0.13
A small foundation for composable() applications.
Combine onion-style middleware, shared providers, and encapsulated modules into a pipeline you can understand from top to bottom.
$bunx rhythmx new my-app
How it works
One request, one pipeline#
Each middleware wraps the next one. The code before next() runs on the way in; the code after it runs on the way back out.
- Requestarrives
- Loggingstarts a timer
- Guardchecks the caller
- Validationparses the body
- Handlerdoes the work
- Handlerreturns
- Interceptorreshapes the result
- Authsets the headers
- Error handlercatches failures
- Responseis sent
Features
Small by design#
- Onion execution.
- Work before and after downstream middleware with
await next(). - Typed composition.
- Providers and explicit context extensions travel through the fluent API.
- Managed dependencies.
- Resolve providers in declaration order and dispose in reverse.
- Explicit boundaries.
- Keep module fields private until you choose to export them.
- Bun-native.
- Bun.serve, WebSockets, Bun.redis, Bun.CookieMap. No adapters.
Ecosystem
With Rhythm you can#
- You canBuild a pipelineCompose middleware and manage shared dependencies.@rhythmjs/rhythm
- You canHandle a requestRoute Web-standard requests, served on Bun.serve.@rhythmjs/router
- You canHold a connectionWebSocket routing on Bun's own model and pub/sub.@rhythmjs/ws
- You canValidate a requestSchema validation, interception, and exception filters.@rhythmjs/middleware
- You canGuard the edgesCORS, CSRF protection, and secure headers.@rhythmjs/security
- You canPersist the stateDrizzle, Prisma, MikroORM, and MongoDB wiring recipes.data
- You canRun it on timeCron, interval, and timeout jobs with an in-house engine.@rhythmjs/schedule
- You canProve it worksModule mocks, a fetch test client, CLI and WS harnesses.@rhythmjs/testing
Why Rhythm
Philosophy#
A framework should be something you compose, not something you inherit.
Types flow with the request#
When a middleware contributes something to the request context, such as a validated body, a session, or a request id, that contribution is visible in the types of every handler that runs after it.
Explicit beats magical#
There are no decorators, no dependency-injection containers, no file-system conventions, and no hidden execution order.
Start building
Begin with the quick start, follow the step-by-step tutorial from a first controller to a production app, read the philosophy behind the design, or create a project with bunx rhythmx new from the starter template for a Nest-style skeleton. If you already know the model, jump to the API reference.