JSON Schema Generator from JSON
Infer a draft-07 JSON Schema from a sample object or object array, then review it before using it as a contract.
Open toolJSON Schema Validator
Validate JSON against a draft-07 or 2020-12 schema. Review error paths without sending the documents to a server.
Free to useNo sign-upRuns in your browser
Enter your details
Enter the inputs, then select Validate JSON.
Your result
Enter your details
Result will appear here
How JSON Schema Validator works
Compile a local JSON Schema with AJV and formats support and validate the supplied JSON without coercion.
Supports draft-07 and draft 2020-12, local references and standard format checks. Remote references are not fetched. Inputs and schema complexity are bounded in a timed worker. The tool does not add defaults, coerce values or prove your business rules are complete.
How to use JSON Schema Validator
Paste the JSON document and a local draft-07 or 2020-12 schema, then inspect the validation status and any error paths.
Paste JSON and its local schema
Use a schema object or boolean schema. Supported drafts are draft-07 and 2020-12; an omitted $schema uses draft-07. Place definitions in the same schema for local fragment references.
Input and settings
Validate JSON against the schema
Run Validate JSON. The worker compiles the supplied schema and checks the data with format validation enabled. It does not coerce values, insert defaults or fetch remote schemas.
Tool result
Read schema mismatch paths
Read Valid JSON or Schema mismatch. When mismatches appear, use Data path, Keyword, Message and Details to locate the issue. Correct the data or schema according to the intended contract, then validate again.
Review the details
Tasks for JSON Schema Validator
Check example documents against a schema and inspect the reported mismatches.
Check an API payload example
Validate a response against the contract you supply. This does not establish that the contract includes every business rule.
Test required and typed fields
Try valid and invalid examples to check required entries, data types and standard formats. Values are not coerced or filled with defaults.
Review a generated schema
Paste a schema from JSON Schema Generator and test additional representative payloads. Edit inferred requirements when they do not fit the intended contract.
Read JSON Schema mismatch paths and keywords
Distinguish an evaluated schema mismatch from a document or schema that could not be parsed or compiled.
Valid JSON means the document passes the supplied supported schema; it does not prove the schema covers every business rule. Schema mismatch lists up to 100 validation errors. Malformed JSON, unsupported references or a schema compilation problem instead produce an input error.
Check local references and JSON Schema limits
Review the selected schema draft, references and numeric representation before retrying a failed validation.
Represent integers outside JavaScript’s safe range as strings where the contract allows them. JSON data and schema inputs each accept up to 100,000 characters. Schemas are bounded at 5,000 inspected nodes and 40 nesting levels, with pattern strings up to 300 characters.
Only local fragment references are supported; remote schemas are not fetched. Validation runs in a timed worker, so complex patterns or recursive schemas may need a smaller representative document. The checker does not change values to make them fit the schema.
More free tools to try
Choose another tool for your next calculation, conversion, or text task.
Markdown Editor
Write Markdown, update the rendered preview and download the Markdown or HTML when it is ready.
Open tool
CSV Validator
Check CSV quoting and consistent column counts, then review the record count and selected delimiter.
Open tool
Image Metadata Remover
Create a newly encoded PNG, JPEG or WebP from a local image and remove its original embedded metadata.
Open tool
HTML Sanitizer
Remove scripts, event handlers and unsupported markup from basic HTML. Review the cleaned fragment and a contained preview.
Open toolValidate JSON against your schema
Paste a supported JSON Schema and sample document, then inspect the status and reported mismatch paths.
JSON Schema Validator: common questions
Answers about using JSON Schema Validator and understanding its results.
Will it download a referenced schema?
No. Provide definitions inside your schema; remote references are unsupported.
Are values changed to fit the schema?
No. Validation does not coerce values or insert defaults.