🏗️ JSON Schema Builder

Auto-generate JSON Schema draft-07 from any JSON, or build visually. Export for OpenAI & Anthropic tool calling.

About JSON Schema Builder

Writing JSON schemas by hand is tedious and error-prone — especially when your data structure is nested. This tool takes any JSON sample you paste in and instantly generates a matching JSON Schema (draft-07), saving you from hours of boilerplate. You can also build schemas visually by adding fields, types, and constraints through a point-and-click UI instead of writing raw JSON.

This is especially handy when working with OpenAI function calling or Anthropic tool use, where you need to define a precise tool schema. Paste your example response, get a clean schema, and copy it straight into your AI project. Everything runs in the browser — nothing is sent anywhere.

Add fields to build your schema interactively.

JSON schema OpenAI function Anthropic tool use schema generator auto-generate