JSON Schema Validator
Paste your JSON data and JSON Schema — validate instantly in your browser with clear, readable error messages.
JSON Schema Validator lets you paste any JSON document and its corresponding schema and instantly see whether they match — with clear, readable error messages. No uploading files, no accounts, no ads. Everything runs in your browser so your data never leaves your device.
How to Validate JSON Against a Schema
- Paste your JSON data into the left panel.
- Paste your JSON Schema into the right panel.
- Click Validate — results appear instantly below.
- Review any validation errors with line references and plain-English descriptions.
- Fix your JSON or schema and re-validate as many times as you need.
Why Use Flipper File to Validate JSON Schemas?
- Supports JSON Schema drafts 4, 6, 7, 2019-09, and 2020-12 — works with whatever schema version you're using
- Clear error messages — errors show the exact path and a human-readable explanation, not cryptic technical codes
- 100% browser-based — your JSON data never leaves your computer
- No login or account required — open the page and start validating immediately
- Shareable schema snippets — perfect for debugging API contracts, config files, and data pipelines
- Free forever — no trial, no credits, no paywall
Frequently Asked Questions
What is JSON Schema?
JSON Schema is a vocabulary for describing the structure and constraints of JSON data. It lets you define what fields are required, what types values should be, and what formats are acceptable — useful for validating API requests, config files, and data pipelines.
Which JSON Schema draft versions are supported?
The validator supports drafts 4, 6, 7, 2019-09 (draft-08), and 2020-12 (the latest). The tool auto-detects the draft based on the $schema keyword in your schema, or defaults to the latest draft if none is specified.
Does my JSON stay private?
Yes — all validation happens entirely in your browser using JavaScript. Nothing is sent to any server. Your data stays on your device.
What kinds of errors does the validator report?
The validator reports type mismatches, missing required fields, pattern violations, minimum/maximum constraint failures, enum violations, and additionalProperties violations — with the JSON path to the failing value.
Can I validate JSON without a schema?
Yes — paste just JSON into the left panel and click Check JSON to verify that it is syntactically valid JSON, even if you don't have a schema to validate against.
What's the difference between JSON validation and JSON Schema validation?
JSON validation checks that your text is syntactically valid JSON (proper brackets, quotes, commas). JSON Schema validation goes further — it checks that the data structure matches rules you've defined, such as required fields, value types, and string formats.
Can I use this to validate API request/response bodies?
Absolutely. Paste your API schema (e.g. from an OpenAPI spec) into the schema panel and paste an example request or response into the JSON panel. The validator will catch any contract violations instantly.
Is there a file size limit?
There's no hard limit — the tool runs in your browser, so performance depends on your device. JSON files up to several megabytes work fine on any modern machine.