How to Use TypeScript 5.6 and Zod 3.23 for Type-Safe AI API Development with FastAPI Building AI-powered APIs requires seamless coordination between backend logic (often Python with FastAPI) and frontend or client-side consumers (typically TypeScript). Type mismatches between these layers are a common source of runtime errors, especially when handling complex AI request/response payloads like prompt inputs, model parameters, and generated outputs. This guide walks you through using TypeScript 5.6 and Zod 3.23 to enforce end-to-end type safety for AI APIs built with FastAPI. Prerequisites Python 3.10+ installed locally Node.js 18+ and npm/yarn Basic knowledge of FastAPI, TypeScript, and REST APIs Optional: A mock or real AI model endpoint (we’ll use a mock for this guide) Step 1: Set Up the FastAPI Backend FastAPI is a modern Python web framework that uses Pydantic for data validation, making it a natural fit for type-safe API development.…