Build type-safe APIs with Hono - fast, lightweight routing for Cloudflare Workers, Deno, Bun, and Node.js. Set up routing patterns, middleware composition, request validation (Zod/Valibot/Typia/ArkType), RPC client/server with full type inference, and error handling with HTTPException. Use when: building APIs with Hono, setting up request validation with schema libraries, creating type-safe RPC client/server communication, implementing custom middleware chains, handling errors with HTTPException