Mastering Type-Safe API Design with Zod and TypeScript

In the modern web ecosystem, static typing with TypeScript isn’t enough. You need runtime validation to ensure the data entering your system is actually what you expect. Enter Zod.

Why Zod?

Zod is a TypeScript-first schema declaration and validation library. Unlike JSON Schema or other tools, Zod provides deep type inference out of the box.

Building a Schema

Defining a user profile schema is straightforward:

import { z } from "zod";

const UserSchema = z.object({
  id: z.string().uuid(),
  username: z.string().min(3).max(20),
  email: z.string().email(),
  age: z.number().optional(),
});

Inference Magic

The real power comes from the z.infer helper:

type User = z.infer<typeof UserSchema>;

This single line keeps your runtime validation and your TypeScript types in perfect sync.

Stay tuned for more guides on integrating Zod with frameworks like Next.js and Hono.