@api-introspect/fastify

Fastify route introspection. Discover endpoints and input/output schemas.

Install

npm install @api-introspect/fastify

Peer dependency: fastify (>=4)

Quick Start

import { introspection } from '@api-introspect/fastify'
import Fastify from 'fastify'

const app = Fastify()

await app.register(introspection, {
  meta: { name: 'My API' },
})

app.get('/user', {
  schema: {
    description: 'List all users',
    response: { 200: UserArraySchema },
  },
}, handler)

await app.listen({ port: 3001 })

Then query /_introspect to get all endpoints with their schemas:

curl http://localhost:3001/_introspect

API

introspection

Fastify plugin that registers an introspection endpoint. Uses Fastify's onRoute hook to automatically collect all routes.

app.register(introspection, options)

introspectRoutes(routes, options?)

Low-level function that converts an array of route info into EndpointInfo[].

Options

interface IntrospectionPluginOptions {
  enabled?: boolean // Default: true
  path?: string // Default: '/_introspect'
  serializer?: Serializer // Default: 'json'
  include?: string[] // Include only these path prefixes
  exclude?: string[] // Exclude these path prefixes
  meta?: {
    name?: string // API name
    description?: string // Appended to generated description
  }
}

Features

• Automatic route collection: Uses Fastify's onRoute hook, no manual registration needed
• Lazy evaluation: Introspection payload computed on first request, then cached
• HTTP method mapping: GET/HEAD/OPTIONS become query, POST/PUT/PATCH/DELETE become mutation
• Schema extraction: Reads from Fastify's native schema system (body, querystring, params, response)
• Unified input: All input schemas use input array with in field ('path', 'query', 'body')
• Response priority: Picks response schema by status code (200 > 201 > 202 > 204)
• Schema compaction: Strips noise from JSON Schema for cleaner output

License

MIT