Which one should I pick for a new project?

I can help you understand the architectures and design patterns of both frameworks to inform your decision, but the choice depends on your specific project needs. Let me outline what distinguishes them:

honojs/hono

Design philosophy: Built on Web Standards, designed for multi-runtime environments.

• Works across Cloudflare Workers, Fastly Compute, Deno, Bun, Vercel, AWS Lambda, Node.js
• Ultralight (hono/tiny under 12kB) with zero dependencies
• Modern TypeScript-first API with strong type inference (evident from extensive client typing tests in [src/client/client.test.ts])
• Middleware composition via compose() function [src/compose.test.ts]

koajs/koa

Design philosophy: Node.js-focused framework built on established conventions.

• Version 3.2.1 with ESM support [package.json:L1-L40]
• Uses standard Node.js patterns (Express-like middleware)
• Request/response manipulation via context object (ctx.query, ctx.attachment, etc.)
• Established ecosystem with mature middleware patterns

Decision factors:

1. Runtime flexibility: Need edge computing or multi-runtime? → Hono
2. Node.js-only: Traditional server deployment? → Koa is battle-tested
3. Type safety: Need strong TypeScript inference for client/server sync? → Hono shines here
4. Project scale: Greenfield vs. migrating from Express/Koa ecosystem?
5. Bundle size matters: Serverless/edge? → Hono's lightweight approach wins

I'd recommend examining the actual routing, middleware, and API patterns in depth before deciding.

FOLLOW_UPS:

• How does Hono's routing performance compare to Koa's?
• What's the middleware composition pattern difference?
• Does either have better error handling patterns?