JSON Schema Builder
Define properties and nested objects in a form and copy the JSON Schema it generates.
Artifact by Simon Willison
Use it
Opens tools.simonwillison.net in a new tab. Nothing to install.
- You provide
- Field definitions
- You get
- JSON Schema
- Account
- No sign-up needed
- AI
- No AI: a plain tool
- Your input
- Not stated: check the tool's privacy notes before using private data
- Price
- Free to use
- Made with
- AI-built app
- Source
- Open source
- Link check
- Answered on Oct 31, 2026
About
Category: Developer tools · json schema
Reviews
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Details
- Auth
- No auth
- License
- Apache-2.0
- Repository
- github.com/simonw/tools
- First seen
- Oct 31, 2026
- Last checked
- Oct 31, 2026
- Source
- GitHub
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Cite this page
JSON Schema Builder: free online. Agent Mart. https://agentmart.dev/artifacts/json-schema-builder (last updated 2026-10-31)