Features Overview

OneBun is a complete, batteries-included backend framework for Bun.js. It provides everything needed to build production-grade TypeScript services — from HTTP routing to database integration, from message queues to observability.

Core Framework (@onebun/core)

Dependency Injection & Modules

NestJS-inspired module system with automatic constructor-based DI, module imports/exports, and service scoping. → API Reference

Controllers & Routing

Decorator-based HTTP controllers with @Get, @Post, @Put, @Delete, @Patch. Path parameters, query parameters, body parsing, header extraction. Standardized ApiResponse format across the application. → API Reference

Guards

Custom guard support for authentication and authorization. Write guard functions and apply them via decorators to protect routes. → API Reference

Interceptors

Universal handler wrapping across HTTP, WebSocket, and Queue transports. Use @UseInterceptors() at any level. Built-in: LoggingInterceptor, TimeoutInterceptor, CacheInterceptor. → API Reference

Middleware

Request/response middleware with @UseMiddleware decorator. Supports middleware chaining on individual routes. → API Reference

File Upload

Built-in multipart/form-data and JSON+base64 file upload support. @UploadedFile() for single files, @UploadedFiles() for multiple, @FormField() for non-file form fields — all with automatic content type detection. → API Reference

Cookie Handling

Extract cookie values directly with @Cookie() decorator. Works alongside @Header(), @Query(), and other parameter decorators. → API Reference

Static file serving

Serve a static directory (e.g. SPA build) from the same host and port as the API. Configure static.root, optional pathPrefix and fallbackFile (e.g. index.html) for client-side routing. → API Reference

WebSocket (@onebun/core)

WebSocket Gateway

Decorator-based WebSocket handlers with @WebSocketGateway, @OnMessage. Built on Bun's native WebSocket support for maximum performance.

Socket.IO Support

Optional Socket.IO adapter for browser compatibility, rooms, namespaces, and broadcasting.

Typed WebSocket Client

Auto-generated typed client for type-safe frontend ↔ backend WebSocket communication. → API Reference

Microservices (@onebun/core)

OneBunApplication Multi-Service Mode

Run multiple services from a single codebase and Docker image:

• Development: all services in one process (bun run src/index.ts)
• Production: one service per process (ONEBUN_SERVICES=users bun run src/index.ts)
• Flexible: any combination via environment variables

Inter-Service Communication

Typed HTTP clients with createServiceDefinition + createServiceClient. HMAC authentication for service-to-service calls.

Kubernetes-Ready

Environment-based service selection, external service URL configuration, single Docker image for all services. → Multi-Service Example

Validation (@onebun/core + ArkType)

Out-of-the-Box Validation

ArkType is re-exported from @onebun/core — no additional packages, no bridge libraries, no Swagger patches. One schema gives you:

• TypeScript type (compile-time safety)
• Runtime validation (request body, query params)
• OpenAPI 3.1 schema (auto-generated documentation)

Install the framework — validation and OpenAPI work. No nestjs-zod, no patchNestJsSwagger(), no setup.

@Body() Validation

Pass ArkType schema to @Body decorator for automatic validation with typed error responses. → API Reference

API Documentation (@onebun/docs)

OpenAPI Auto-Generation

Automatic OpenAPI 3.1 spec from decorators and ArkType schemas. Install @onebun/docs and get Swagger UI with zero configuration.

Documentation Decorators

@ApiTags, @ApiOperation, @ApiResponse for additional metadata. → API Reference

Database (@onebun/drizzle)

Drizzle ORM Integration

Schema-first approach with full type inference. Supports PostgreSQL and SQLite (via bun:sqlite).

Migrations

• CLI: bunx onebun-drizzle generate / push / studio
• Programmatic: generateMigrations(), pushSchema()
• Auto-migrate on startup (enabled by default — no configuration needed)

Repository Pattern

BaseRepository with built-in CRUD operations, custom queries via Drizzle query builder. → API Reference

Queue & Scheduler (@onebun/core + @onebun/nats)

Queue System

Background job processing with multiple backends:

• In-memory — zero config, for development and simple use cases
• Redis Pub/Sub — distributed queues via Redis
• NATS — high-performance messaging (via @onebun/nats)
• JetStream — persistent, at-least-once delivery (via @onebun/nats)

Scheduler

Cron-like task scheduling with the same backend options. → API Reference

Caching (@onebun/cache)

CacheModule

• In-memory cache — with TTL, max size, cleanup intervals
• Redis cache — with shared connection pool support
• Batch operations: mget, mset
• Cache-aside, invalidation, and warming patterns → API Reference

HTTP Client (@onebun/requests)

createHttpClient()

Full-featured HTTP client with:

• Authentication: Bearer, API Key, Basic, HMAC (inter-service)
• Retries: fixed, linear, exponential backoff strategies
• Typed responses: ApiResponse<T> with success/error discrimination

Typed Service Clients

createServiceDefinition() + createServiceClient() for type-safe inter-service REST communication without code generation. → API Reference

Observability

Prometheus Metrics (@onebun/metrics)

• Automatic HTTP request metrics (duration, count, status codes)
• System metrics (CPU, memory, event loop, GC)
• Custom metrics: Counter, Gauge, Histogram
• Decorator-based: @Timed(), @Counted(), @Gauged()
• Endpoint: GET /metrics → API Reference

OpenTelemetry Tracing (@onebun/trace)

• Automatic HTTP request tracing
• @Span() decorator for custom spans
• Trace context propagation in logs
• Configurable sampling, export to external collectors → API Reference

Structured Logging (@onebun/logger)

• JSON (production) and pretty (development) output
• Log levels: trace, debug, info, warn, error, fatal
• Child loggers with context inheritance
• Automatic trace context in log entries → API Reference

Configuration (@onebun/envs)

Type-Safe Environment Variables

• Schema definition with Env.string(), Env.number(), Env.boolean(), Env.array()
• Validation, defaults, transforms
• Sensitive value masking in logs
• .env file support
• Per-service overrides in OneBunApplication multi-service mode → API Reference

Production Features

Graceful Shutdown

Enabled by default. Handles SIGTERM/SIGINT, closes HTTP server, WebSocket connections, and Redis connections.

Shared Redis Connection

Single Redis connection pool shared between Cache, WebSocket, and Queue modules. Reduced memory footprint and connection count.

Effect.js Integration

Internal architecture built on Effect.js for type-safe side effect management. Optional Effect API for advanced use cases.

For NestJS Developers

If you're coming from NestJS, here's what to expect:

Same patterns

• @Module, @Controller, @Service decorators
• Constructor-based dependency injection
• Module imports/exports for service sharing
• Guards for route protection
• Middleware support

Improved in OneBun

• Validation: ArkType schema = TypeScript type = OpenAPI spec = runtime validation, wired out of the box (NestJS teams can achieve similar workflows with nestjs-zod — OneBun ships it without extra packages)
• Microservices: Single Docker image, env-based service selection (vs separate entry points in NestJS)
• Observability: Prometheus metrics + OpenTelemetry tracing built-in (vs community packages in NestJS)
• Performance: Bun.js native, no Express/Fastify adapter layer
• Configuration: Type-safe env schema with sensitive value masking (vs @nestjs/config)

Different approach

• ArkType instead of class-validator/class-transformer
• Drizzle ORM instead of TypeORM (schema-first, not entity-first)
• Effect.js internally (optional for application code)
• Bun.js runtime only (not Node.js compatible)

Not yet available

• GraphQL integration (post-1.0 consideration)
• CQRS module
• Extensive third-party ecosystem

Feature Comparison

How OneBun compares to other TypeScript backend frameworks.

Legend: ✅ built-in · 🔌 plugin/adapter · 👥 community · ❌ none

Feature	OneBun	NestJS	Hono	Elysia
DI / IoC container	✅ Effect.Context	✅ Custom container	❌	❌
Module system	✅ @Module	✅ @Module	❌	❌
Decorator routing	✅	✅	❌	✅
Guards / Auth	✅	✅	👥	👥
Middleware	✅	✅	✅	✅
Validation	✅ ArkType	🔌 class-validator	👥	✅ TypeBox
OpenAPI generation	✅ Auto from schemas	🔌 @nestjs/swagger	👥	✅
WebSocket	✅ Native + Socket.IO	🔌 @nestjs/websockets	👥	✅
File upload	✅	🔌 multer	👥	✅
Queue / Scheduler	✅ In-memory, Redis, NATS	🔌 @nestjs/bull	❌	❌
Prometheus metrics	✅ @onebun/metrics	👥	❌	❌
OpenTelemetry tracing	✅ @onebun/trace	👥	👥	👥
Structured logging	✅ @onebun/logger	👥	👥	👥
Database (ORM)	✅ Drizzle	🔌 TypeORM/Prisma	❌	❌
Caching	✅ In-memory + Redis	🔌 @nestjs/cache-manager	❌	❌
Env validation	✅ @onebun/envs	🔌 @nestjs/config	❌	❌
Multi-service	✅ Single image	❌	❌	❌
Graceful shutdown	✅	🔌	❌	❌
GraphQL	❌ (post-1.0)	🔌 @nestjs/graphql	👥	👥
Interceptors / Pipes	✅	✅	❌	✅ hooks
CQRS	❌	🔌 @nestjs/cqrs	❌	❌
Node.js support	❌ Bun only	✅	✅	❌ Bun only
Third-party ecosystem	🆕 Growing	✅ Mature	✅ Growing	👥 Growing