Building an Edge REST API with Hono.js + TypeScript — From Bun Local Server to Cloudflare Workers

If you've ever built a REST API with Express, you've probably felt it. Middleware registration, type definitions, body parser setup, connecting Joi or Zod... the structure is simple, but the boilerplate is excessive. When I first saw Hono, I was skeptical. "Another Express clone," I thought. That changed when I actually ran it. Bottom line: Hono v4 is more than just lightweight and fast. TypeScript type inference flows naturally all the way to route handlers. Zod validation connects via a single official package. On Bun, response times are noticeably faster than Express. Everything in this post is based on what I ran in a sandbox in June 2026. Why Hono — Compared to Express and Fastify Understanding where Hono fits means answering three questions. Bundle size : Hono v4 core is about 12KB. Express is 58KB, Fastify is 77KB. The gap might not sound dramatic, but in edge environments like Cloudflare Workers or Deno Deploy, bundle size directly affects cold start time. Edge functions sometimes initialize a new runtime per request — smaller means faster first response. Runtime compatibility : Express is Node.js-only. Fastify targets Node.js by default. Hono was designed from the start to "run anywhere." The same code deploys to Bun, Deno, Cloudflare Workers, Node.js, and AWS Lambda Edge. TypeScript support : Express requires @types/express as a separate install, and properties added to req via middleware don't get type inference. Hono is written in TypeScript from the ground up, and the Hono<{ Bindings: Env; Variables: Variables }> generic gives you type-safe access to environment variables and middleware state. I'm not saying Hono is the right choice for every situation. If your team is deeply invested in Express, or you need a mature plugin ecosystem, there's no compelling reason to switch. But if edge deployment is the goal, or you want type safety from day one, Hono is the most convincing TypeScript API framework right now. Installation and First Server — Response in