About Schema.biz
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Schema.biz builds free, browser-based tools for developers and SEO professionals who work with structured data, database schemas, and API specifications. Every tool runs in your browser: what you paste isn't uploaded, there's no account to create, and there's nothing to install. The site measures visits with Google Analytics and Cloudflare Web Analytics, and records which checks the tools run, never what you paste; the privacy policy explains what each records.
Who builds it
I'm Tim Fulton. I build and maintain Schema.biz, its tools and its guides, at Horizon Two Labs, which operates the site. The guides carry my name as their author.
Why it exists
Structured data tells search engines what a page means, database schemas define how data is stored and related, and API schemas describe how services talk to each other. The everyday jobs around them — generating a JSON-LD block, checking it, turning SQL into a diagram, validating a payload against a schema — are small, and they shouldn't require a subscription or uploading your work to someone's server. Schema.biz puts those jobs in free tools that run in the browser.
Your input stays in your browser
Processed on your device
All Schema.biz tools execute JavaScript directly in your browser. Your SQL schemas, JSON-LD markup, API specifications, and anything else you paste are processed on your machine and never uploaded; no server stores tool input. It only leaves your device when you choose, for example with the "Test in Google" buttons, which copy your markup and open Google's Rich Results Test for you to paste it into. Check a URL in the markup checkers sends only the address you enter: our server fetches that page as SchemaBizBot and sends it back to your browser to check. We record anonymous usage metadata (which tool, which schema types, which errors, and the page URL being checked) to improve the tools, never what you paste. See the privacy policy.
What we offer
Markup tools
Generate, validate, and optimize structured data markup for search engines. The JSON-LD Generator has forms for 12 common Schema.org types. The Schema Validator checks your JSON-LD for errors, missing properties, and rich result eligibility. The AI Search Optimizer scores how well your structured data describes your content for AI-powered search engines like ChatGPT Search and Perplexity. The Schema Audit checks all the JSON-LD in a page's HTML in one pass.
Database tools
Design and analyze relational database schemas visually. The Schema Designer lets you lay out tables and relationships on a diagram and export SQL. SQL to Diagram generates ER diagrams from CREATE TABLE statements. The Query Visualizer shows which tables and columns a SELECT query touches. Schema Diff compares schema versions and generates a migration script to review. The Templates library has 10 starter schemas.
API tools
Build and validate API specifications. The JSON Schema Validator supports Drafts 4, 6, 7, 2019-09, and 2020-12. JSON to Schema infers schemas from example data. The OpenAPI Editor previews your spec as you write it. The Schema Converter turns JSON Schema, TypeScript, or GraphQL into Zod, Pydantic, Go, and more. The Mock Data Generator produces test data from schemas, and the Breaking Change Detector compares schema versions and flags breaking changes.
Learning resources
The Learning Hub has free guides on structured data markup, database design, JSON Schema, API versioning, and AI search optimization.
How the tools are tested
Automated tests run on every pull request. Unit tests cover the logic underneath the tools, such as the JSON Schema draft handling, the diagram layout, the syntax highlighting, and the Generator's share links. End-to-end tests load every page of the site on desktop and phone-sized screens, fail on any page error, and run several of the tools on sample input.
How the site is built
The site is built with Astro, with React components on the tool pages that need interactivity, and styled with Tailwind CSS. It is rendered to static pages at build time and served by Cloudflare's global network. Every transformation, validation, and export runs as JavaScript inside the page you are viewing. The site's one server endpoint, a Cloudflare Worker, stores the anonymous tool usage records described in the privacy policy. JSON Schema validation uses Ajv, the OpenAPI Editor parses YAML with js-yaml, and the database tools use a custom SQL parser.
Contact
Have feedback, found a bug, or want to suggest a new tool? Email hello@schema.biz or use the link below. Feedback helps decide what to build next.