JSON Schema Validator
Validate JSON against a JSON Schema subset and list every violation.
- Runs locally in your browser
- No upload required
Try it
Supported formats
Privacy
Runs entirely in your browser. Your input is never uploaded, stored, or sent to a third party.
The document is valid against the schema.
How it works
- Parsed the schema and the document with the verbatim JSON scanner.
- Applied each supported keyword, recursing into properties and items.
- Reported every violation with a JSON Pointer path and the failing keyword.
- Unsupported keywords are reported as warnings; $ref and remote schemas are out of scope (no network).
Methodology
- Parse the schema and document with the F054 verbatim scanner.
- Apply each supported keyword recursively, tracking a JSON Pointer path.
- Record violations with their keyword and unsupported keywords as warnings.
Usage
- Paste the JSON document.
- Paste the JSON Schema.
- Run the tool and read the validity result, every violation and any unsupported-keyword warnings.
Examples
These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.
Valid document
{
"text": "{\"name\":\"Ada\",\"age\":36}",
"schema": "{\"type\":\"object\",\"required\":[\"name\",\"age\"],\"properties\":{\"name\":{\"type\":\"string\"},\"age\":{\"type\":\"integer\",\"minimum\":0}}}"
}Type violation
{
"text": "{\"age\":\"thirty-six\"}",
"schema": "{\"type\":\"object\",\"properties\":{\"age\":{\"type\":\"integer\"}}}"
}Limitations
Reading violations
Each line starts with the JSON Pointer of the failing value and the keyword that failed, so a nested error is easy to locate.
Frequently asked questions
- Which schema keywords are supported?
- type, enum, const, required, properties, additionalProperties (boolean), items, the numeric and length bounds, pattern, allOf, anyOf, oneOf and not.
- What happens to an unsupported keyword?
- It is listed as a warning so it is never silently treated as satisfied.
- Is my data uploaded?
- No. The document and schema are processed entirely in your browser and are never sent anywhere.
Sources
- JSON Schema Draft 2020-12 — JSON Schema
- JSON Schema — Understanding JSON Schema — JSON Schema
Send feedback
Tell us if this tool helped, report a problem, or suggest a tool. Only the message you type is sent — never the input you used in the tool.
Was this tool useful?
Prefer to write to us directly? See the contact page.