elysiajs/elysia

Health v2 · maintenance only

Adoption not part of the score

18975 stars · 574 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Elysia is a TypeScript backend web framework built for Bun, emphasizing end-to-end type safety, schema-driven validation, and ergonomic developer experience. It generates OpenAPI docs and client types from a single schema source and claims top-tier benchmark performance.

Use cases

• build a fast REST API in TypeScript on Bun
• get end-to-end type safety between server and client like tRPC
• auto-generate OpenAPI documentation from route schemas
• build realtime apps with WebSockets and server-sent events
• replace Express or Fastify with a faster Bun-native framework
• validate request bodies and infer handler types from one schema

When to choose

• you use (or are willing to adopt) the Bun runtime
• you want type-safe APIs with minimal boilerplate and great DX
• raw HTTP throughput matters for your service

When to avoid

• your deployment targets Node.js or Deno exclusively and you can't use Bun
• you need a mature ecosystem of middleware beyond what Elysia plugins cover
• your team is locked into an existing Express/NestJS codebase

Facets

framework · maturity active

web-framework http-server routing websocket middleware api-framework web-development backend apis developer-tools bun cross-platform end-to-end-type-safety openapi typebox-validation eden-rpc server-sent-events high-performance typescript web-server

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markdown · JSON · MCP: product_card(name="elysiajs/elysia")