Which OpenAPI Generator to Use? Zod OpenAPI vs Hono OpenAPI vs Hono Docs Generator

[bestickley]

Which OpenAPI Generator to Use? What's difference between Zod OpenAPI vs Hono OpenAPI vs Hono Docs Generator?

[JackyST0]

Here's a comparison of the three OpenAPI generators for Hono:

Quick Comparison

Feature	Zod OpenAPI	Hono OpenAPI	Hono Docs Generator
Schema validation	Zod (runtime)	Zod (runtime)	TypeBox/Valibot
Type inference	✅ Excellent	✅ Excellent	✅ Good
Swagger UI	✅ Built-in	✅ Built-in	✅ Built-in
Maintenance	Active	Active	Active
Learning curve	Medium	Medium	Easy

Recommendations

Use @hono/zod-openapi if:

• You're already using Zod in your project
• You want tight integration between validation and OpenAPI spec
• You need the most mature solution

import { OpenAPIHono, createRoute, z } from '@hono/zod-openapi'

const route = createRoute({
  method: 'get',
  path: '/users/{id}',
  request: {
    params: z.object({ id: z.string() })
  },
  responses: {
    200: { description: 'User found' }
  }
})

Use hono-openapi if:

• You want a lighter alternative
• You prefer a different API style

Use Hono Docs Generator if:

• You want the simplest setup
• You're okay with less customization

My Recommendation

Go with @hono/zod-openapi - it's the most widely used, well-documented, and has the best community support.

Docs: https://hono.dev/examples/zod-openapi

---

If this solves your problem, please mark it as the answer! ✅

[paolostyle]

Shameless plug as I'm an author but I'd like to recommend my library hono-zod-openapi: https://github.com/paolostyle/hono-zod-openapi

The main goal of this library is easy adoption to existing codebases. With @hono/zod-openapi you need to write your code completely differently from how you'd normally use Hono which for me was a huge turnoff, with my library it's as simple as adding a middleware. I think it's very well typed, has built in validation (so you no longer need zod-validator) and I'm working on strictly typed responses, should be out soon.

The only real downside is that it's not as flexible when it comes to library choice as it only supports Zod v4 (for v3 use 0.x versions, but I won't be adding any new features there).

A simple example on how it works:

import { Hono } from 'hono';
import * as z from 'zod';
import { createOpenApiDocument, openApi } from 'hono-zod-openapi';

export const app = new Hono().get(
  '/user',
  openApi({
    tags: ['User'],
    responses: {
      200: z.object({ hi: z.string() }).meta({ examples: [{ hi: 'user' }] }),
    },
    request: {
      query: z.object({ id: z.string() }),
    },
  }),
  (c) => {
    // works identically to @hono/zod-validator
    const { id } = c.req.valid('query');
    return c.json({ hi: id }, 200);
  },
);

// this will add a `GET /doc` route to the `app` router
createOpenApiDocument(app, {
  info: {
    title: 'Example API',
    version: '1.0.0',
  },
});

Give it a try, I think the DX is pretty awesome.