KosmoJS generates an OpenAPI 3.1 specification directly from your route definitions.

Route structure, TypeScript types, VRefine constraints, parameters, responses - all reflected in the spec automatically. No manual schema authoring, no annotation layers.

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Enable OpenAPI

Simply add it to your source folder's kosmo.config.ts:

import { defineConfig } from "@kosmojs/dev";

export default defineConfig({
  backend: {
    stack: "hono",
    base: "/api",
    openapi: {
      outfile: "openapi.json",
      openapi: "3.1.0",
      info: { title: "My API", version: "1.0.0" },
      servers: [{ url: "https://api.example.com/api" }],
    },
  },
});