JSON Schema Builder
Define properties and nested objects in a form and copy the JSON Schema it generates.
Artifact by Simon Willison
IndexedApache-2.0Developer toolsNo sign-up
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 Nov 1, 2026
About
JSON Schema Builder is an AI-built single-page app in the developer tools category (json schema). It opens in your browser, so there is nothing to install. You provide field definitions and get JSON Schema. It needs no account. It is a plain tool: no AI model is involved. The source code is public on GitHub (simonw/tools).
Category: Developer tools · json schema
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Details
- Auth
- No auth
- License
- Apache-2.0
- Repository
- github.com/simonw/tools
- First seen
- Oct 31, 2026
- Last checked
- Nov 1, 2026
- Source
- GitHub
More from Simon Willison
Cite this page
JSON Schema Builder: free online. Agent Mart. https://agentmart.dev/artifacts/json-schema-builder (last updated 2026-11-01)