Errors
How to validate JSON against a JSON Schema online
- Paste your data into the Data pane on the left.
- Paste your schema into the Schema pane on the right.
- Click Validate. Every failure is reported with the exact data path (e.g.
/users/2/email) and the keyword that rejected it. - Need only a syntax check? Use the JSON validator instead.
JSON Schema vs JSON syntax — which one do I need?
Syntax validation (RFC 8259) checks that the JSON parses. JSON Schema validation checks that the parsed value matches a structural contract — the right types in the right places, required fields present, strings matching patterns, numbers within ranges. Most production APIs want both: the JSON validator for the first, this JSON Schema test tool for the second. Our JSON Schema quickstart walks through the keywords that pull their weight on real services.
Supported keywords
JSONYard's validator covers the most common JSON Schema features:
- Types —
string,number,integer,boolean,null,array,object(and union arrays) - Objects —
properties,patternProperties,additionalProperties,required - Arrays —
items,prefixItems,minItems,maxItems,uniqueItems - Strings —
minLength,maxLength,pattern,format(email, uri, uuid, date, date-time, ipv4) - Numbers —
minimum,maximum,exclusiveMinimum,exclusiveMaximum,multipleOf - Generics —
enum,const,allOf,anyOf,oneOf,not, local$ref
If you need exotic features (remote $ref, full draft 2020-12 vocabulary, if/then/else), use Ajv in your toolchain — that's what real production validation should use.
Need a syntax check first? Use the JSON Validator, or read the blog post on fixing common JSON parse errors.
FAQ
Which draft does this support?
if/then/else, dynamic refs, or remote refs.Why are some errors imprecise?
oneOf we report the overall failure rather than the inner branch errors. This is a tradeoff for code size.Can I validate JSON against a JSON Schema online without uploading?
Where do I get a JSON Schema for an existing JSON document?
quicktype or genson can infer a starter schema from sample data. The JSON Schema quickstart covers what to tighten after generation.