How to generate typed APIs with Cursor

To generate typed APIs with Cursor, you use Cursor’s multi-file reasoning to help you create TypeScript types from your backend routes (or vice‑versa), but the actual typing is produced using real tooling such as Zod, TypeScript interfaces, OpenAPI schemas, or tRPC. Cursor itself does not “generate APIs,” but it can reliably scaffold, maintain, and refactor typed API definitions when you give it clear code and structure. The practical path is: define your API contracts in a single source of truth (Zod, OpenAPI, tRPC), then use Cursor to generate your server handlers and client functions based on those types, ensuring backend and frontend stay in sync.

 

What “typed APIs” means in real practical terms

 

Typed APIs mean that your backend routes have strict input/output definitions, and your frontend automatically gets the correct TypeScript types for calling those routes. This prevents bugs like sending wrong parameters or mis‑handling responses.

Cursor does not invent types; instead, it helps you generate and maintain them correctly when you use real tools like Zod, TypeScript interfaces, OpenAPI, or tRPC.

 

• Zod: JS/TS schema validation library. Cursor works extremely well with it.
• OpenAPI: Industry standard JSON schema for APIs. Cursor can read and generate code from it.
• tRPC: End‑to-end type-safe API framework (TypeScript only).

 

The simplest, most reliable pattern: Zod + Express + Cursor

 

This workflow is stable, beginner‑friendly, and Cursor handles it very well. You create API schemas using Zod, and Cursor helps you auto-generate server handlers and client callers while keeping everything typed.

Here is a minimal working example.

 

// src/schemas/userSchemas.ts
import { z } from "zod"

export const createUserSchema = z.object({
  name: z.string(),
  email: z.string().email()
})

export type CreateUserInput = z.infer<typeof createUserSchema>

 

// src/routes/userRoutes.ts
import express from "express"
import { createUserSchema } from "../schemas/userSchemas"

const router = express.Router()

router.post("/users", (req, res) => {
  const parsed = createUserSchema.safeParse(req.body)  // typed validation
  if (!parsed.success) return res.status(400).json(parsed.error)

  const user = {
    id: "123",
    ...parsed.data
  }

  res.json(user)
})

export default router

 

How to use Cursor to generate the typed client API

 

In Cursor, you can highlight your Zod schema and your Express route, open the Composer, and ask:

"Generate a typed client function for calling this endpoint using fetch and the inferred Zod types."

Cursor will output something like:

 

// src/client/userClient.ts
import { CreateUserInput } from "../schemas/userSchemas"

export async function createUser(input: CreateUserInput) {
  const res = await fetch("/users", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(input)
  })

  if (!res.ok) throw new Error("Failed to create user")

  return res.json()  // correctly typed on return
}

 

The important part: because the types come from real code (Zod schemas), Cursor will always stay accurate and safe.

 

Using Cursor with OpenAPI

 

If your project uses OpenAPI (Swagger), Cursor can read your openapi.yaml or .json file and scaffold real typed clients/servers using tools like openapi-typescript or swagger-ui-express.

A common working approach:

• Create or maintain an openapi.yaml.
• Run npx openapi-typescript openapi.yaml -o src/types/api.ts.
• Use Cursor to generate Express handlers or fetch clients based on the types.

 

Using Cursor with tRPC

 

tRPC already gives you fully typed end‑to‑end APIs. Cursor shines here by helping you generate procedures, refactor routers, or create React hooks. Everything is already type‑safe.

 

// src/trpc/router.ts
import { initTRPC } from "@trpc/server"
import { z } from "zod"

const t = initTRPC.create()

export const appRouter = t.router({
  createUser: t.procedure
    .input(z.object({ name: z.string(), email: z.string().email() }))
    .mutation(({ input }) => {
      return { id: "123", ...input }
    })
})

export type AppRouter = typeof appRouter

 

How Cursor fits into the workflow

 

• You define real schemas (Zod/OpenAPI/tRPC).
• Cursor reads them across the project and auto-generates handlers, clients, or React hooks.
• Because types come from your schemas, Cursor’s output is consistent and safe.
• When you update a schema, Cursor can update all related files.

 

Summary

 

You don’t “generate typed APIs” with Cursor alone. Instead, you use real tooling (usually Zod, OpenAPI, or tRPC) to define your types, and Cursor helps generate or maintain the surrounding code — backend handlers, frontend clients, validation logic, and refactors — while keeping everything typed and synchronized.

This approach is production-safe, easy to maintain, and works perfectly with Cursor’s strengths (multi-file reasoning and consistent edits).