JSON Schema Validator
Validate JSON data against a JSON Schema and see each error marked on the exact line. Pick an example schema or paste your own — everything runs in your browser, so nothing is uploaded. Powered by Ajv.
About the JSON Schema Validator
Updated June 2026 · 100% client-side — your data never leaves your browser.
A JSON Schema describes the shape your JSON should have — which fields are required, their types, allowed values, formats and ranges. Bytewrench's JSON Schema Validator checks a JSON document against a schema and reports every place the data doesn't match, with the exact path to each problem.
It runs entirely in your browser using Ajv, the same validator many production systems rely on, so you can safely check API payloads, config files and other sensitive data without anything being uploaded.
See also: JSON validator, JSON formatter
How to use it
- Paste your JSON Schema into the left panel (Draft-07 and later).
- Paste the JSON data you want to check into the right panel.
- Click Validate to see whether the data conforms, with every error listed.
- Fix the data or the schema and validate again — results refresh as you edit.
Checks types, required fields, enums, patterns, ranges and nested structures with Ajv.
Every violation shows the instance path, the failed keyword and a clear message.
Common formats like email, date-time, uri and uuid are validated when your schema uses them.
Schema and data are validated locally in your browser — neither is ever uploaded.
Frequently asked questions
What is the difference between this and a JSON validator?
A JSON validator only checks that text is syntactically valid JSON. A JSON Schema validator goes further and checks that valid JSON also matches a schema's rules — required fields, types, allowed values and so on.
Which JSON Schema drafts are supported?
The validator uses Ajv and supports Draft-07 by default, which covers the large majority of schemas in use today.
Is my data sent to a server?
No. Both the schema and the data are validated entirely in your browser, and neither is uploaded anywhere.
Does it validate formats like email or date-time?
Yes. When your schema uses the format keyword — for example email, date-time, uri or uuid — those formats are checked as well.