"@context": "https://schema.org", "@type": "Article", "headline": "Your Content", "author": { "@type": "Person", "name": "Jane Smith" }, "datePublished": "2025-03-20", "publisher": { "@type": "Organization", "name": "Schema.biz" }
The Complete Schema Toolkit
Free tools for structured data markup, database design, and API validation. No signup required — everything runs in your browser.
Everything You Need
Three categories of tools covering the full schema lifecycle.
Markup Tools
Generate and validate structured data markup for SEO. JSON-LD, Microdata, and Schema.org made easy.
Database Tools
Design schemas, generate SQL, and build ERDs. Visual tools for database architecture.
API Tools
Build and validate OpenAPI specs, JSON Schema, and API contracts. Design APIs visually.
Featured Tools
The most popular tools to get you started.
JSON-LD Generator
Create structured data markup with a visual editor. Supports all Schema.org types.
AI Search Optimizer
Optimize your schema markup for ChatGPT Search, Perplexity, and Google AI Overviews.
Schema Designer
Design database schemas visually with drag-and-drop. Export SQL for any dialect.
SQL to Diagram
Paste CREATE TABLE statements and instantly generate an interactive ER diagram.
Mock Data Generator
Generate realistic test data from any JSON Schema. Locale-aware, seeded output.
Breaking Change Detector
Compare API schema versions and detect breaking, warning, and safe changes.
Why Schema.biz?
Built with developer trust in mind.
100% Browser-Based
Every tool runs entirely in your browser. Your data never leaves your machine.
Free Forever
All tools are completely free. No premium tiers, no feature gates, no limits.
No Account Required
Start using any tool immediately. No signup, no email, no friction.
Developer-First
Built by developers, for developers. Clean output you can copy straight into your project.
How Schema.biz works
Schema.biz is a static site of client-side tools. Every generator, validator, designer, and converter you find here runs entirely in your browser — there is no backend service that receives your data, no upload step, no server-side processing of any kind. When you paste a JSON-LD snippet into the Validator, the validation runs in JavaScript on your machine and the result appears without a single network request leaving your browser. When you draw a database schema in the Designer, the SQL export is computed locally and downloaded directly. Your content does not transit our infrastructure, because there is no infrastructure between you and the page.
That choice has practical consequences. The first is privacy. Schemas often contain unreleased product names, internal database column names, customer data shapes, partner identifiers, and other details you would rather not paste into a third-party service. With a browser-only architecture, the question of what we do with your data has a simple answer — we never see it. There is no log, no cache, no analytics event that captures what you typed. The second is speed. Without a network round-trip, validators return results as fast as your machine can compute them, which on modern hardware means instantaneously. The third is reliability. The tools work offline once a page has loaded. They work behind corporate firewalls. They keep working if our analytics or ad provider has an outage.
The site itself is built with Astro and deployed as static HTML, CSS, and JavaScript on a global CDN. Every page is pre-rendered, every interactive tool is hydrated only when needed, and the total page weight is small enough to load over a slow connection. We use AdSense and Google Analytics for monetization and traffic measurement; both are clearly disclosed in the privacy policy and neither has access to the contents of any tool. If you prefer to block them entirely, the tools still work — there is no soft paywall, no signed-out experience, no degraded mode.
Browser-only architecture has limits. It works for the schema lifecycle precisely because every transformation we ship — generation, validation, diffing, formatting, mock generation — fits into a few hundred kilobytes of JavaScript. Tools that genuinely need a server, like crawling a third-party URL or persisting your work across devices, are not on the site for that reason. Where a feature would compromise the privacy guarantee, we leave it out rather than dilute the model.
Who uses Schema.biz
Three groups make up the bulk of the site's traffic, and the tools are shaped around their needs.
The first is in-house SEO and content teams at small and mid-sized businesses. Their workflow tends to look like this: a content brief lands in the queue, the writer drafts the page, the SEO lead opens the JSON-LD Generator to produce the matching Article, Product, or LocalBusiness markup, pastes the result into the CMS, and runs the AI Search Optimizer to verify the page is citation-ready before scheduling. They do not need a paid platform with reporting dashboards and seat licenses; they need a fast tool that emits clean output and a validator that explains errors in English. Many of them visit the site every week, never sign up, and never pay a cent — which is exactly the model.
The second is application developers working on backend or full-stack systems. They reach for the Database Designer when starting a new service, paste a colleague's CREATE TABLE statements into SQL to Diagram during code review, run the Schema Diff against a draft migration before opening a pull request, and hit the JSON Schema Validator and Mock Data Generator while wiring up new endpoints. The constant: tools that fit in the few minutes between meetings, not platforms that require onboarding. They share links to specific tool pages with teammates rather than usernames or workspace invites.
The third is freelancers and agencies delivering schema work for multiple clients. They live in the AI Search Optimizer and Schema Audit, running them against client URLs to produce before-and-after reports and to surface quick wins worth billing for. They especially value the no-signup, no-data-retention model, since it lets them work across client accounts without leaking one client's structure to another or maintaining seat licenses for a tool that only runs locally anyway.
All Processing Happens in Your Browser
Schema.biz tools use client-side JavaScript exclusively. Your schemas, database designs, and API specs never touch our servers. What you build stays on your machine.