@api-introspect/trpc

tRPC router introspection. Discover procedures, input/output schemas as JSON Schema.

Install

npm install @api-introspect/trpc

Peer dependencies: @trpc/server (>=11), zod (>=4)

Quick Start

import { withIntrospection } from '@api-introspect/trpc'
import { initTRPC } from '@trpc/server'

const t = initTRPC.create()

const appRouter = t.router({
  user: t.router({
    list: t.procedure.query(() => users),
    create: t.procedure
      .input(z.object({ name: z.string() }))
      .mutation(({ input }) => createUser(input)),
  }),
})

// Add introspection - that's it
const router = withIntrospection(t, appRouter, {
  meta: { name: 'My API' },
})

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

curl http://localhost:3000/_introspect

API

withIntrospection(t, appRouter, options?)

Merges an introspection router into your app router. This is the recommended approach.

createIntrospectionRouter(t, appRouter, options?)

Creates a standalone introspection router you can merge manually.

introspectRouter(router, options?)

Low-level function that extracts EndpointInfo[] from a tRPC router.

Options

interface IntrospectionRouterOptions {
  enabled?: boolean // Default: true
  path?: string // Default: '_introspect'
  serializer?: Serializer // Auto-detected if omitted
  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

• Precomputed: Introspection payload is built at router creation time, not per-request
• Schema conversion: Zod schemas converted to JSON Schema via z.toJSONSchema()
• Stacked inputs: Combines middleware input parsers using z.intersection()
• Serializer detection: Auto-detects JSON, SuperJSON, or custom transformers
• Schema compaction: Strips noise from JSON Schema for cleaner output

License

MIT