One Schema, Zero Drift: How Zod Keeps My Frontend and Backend in Sync

TypeScript catches a lot of bugs. But it has a blind spot: the network boundary. Your server returns { createdAt: string } instead of { created_at: string } , and TypeScript won't say a word. You'll find out at runtime, when the UI renders "undefined" where a date should be. This happens because TypeScript types are erased at compile time. They describe what your code expects , not what actually arrives over the wire. Your frontend type says User , but the API could return anything -- a different shape, extra fields, missing fields, wrong types. TypeScript just trusts you. Zod fixes this by making validation and types the same thing. You define a schema once, in a shared folder, and both sides of the app use it. The server validates incoming requests against it. The client validates forms against it. TypeScript infers types from it. One source of truth, enforced at runtime and compile time. The Shared Schema Start with a /shared folder at the project root. Both server and client import