Data and Schema Validators
Paste a document and find out precisely what is wrong with it: the line, the column, the character the parser stopped on, and — where a schema is involved — which field failed which rule.
Find out why a document will not parse, where the problem is, and whether it matches the shape it is supposed to have.
7 tools
7 tools
- JSON ValidatorJSON ToolsCheck JSON syntax and get the exact line, column and cause of every failure.JSONReport
- JSON ParserJSON ToolsParse JSON, confirm it is valid, and see it as clean indented output.JSONJSON
- JSON RepairJSON ToolsFix common JSON mistakes — quotes, commas, comments — and get valid output.JSONJSON
- JSON Schema ValidatorJSON ToolsValidate a JSON document against a JSON Schema and see every error.JSON + SchemaReport
- JSON to JSON SchemaJSON ToolsGenerate a JSON Schema that describes the shape of an example document.JSONJSON Schema
- JWT DecoderDeveloper ToolsDecode JWT header and payload claims. Signature is not verified.JWTJSON
- Regex TesterDeveloper ToolsTest regular expressions live with match highlighting and capture groups.Pattern + textMatches
Syntax validation and schema validation are different jobs
Syntax validation answers one question: is this text a well-formed document at all? A trailing comma, a single quote where a double quote belongs, an unescaped newline inside a string, a missing closing brace — these stop the parser, and the useful output is a position. That is what the JSON Validator and the JSON Parser give you: the line and column where parsing failed, the surrounding text, and what the parser was expecting when it gave up.
Schema validation assumes the document already parses and asks a harder question: does it have the right shape? A payload can be flawless JSON and still be wrong for its purpose — a string where a number belongs, a required field absent, an enum value that is not in the enum, an array with too few items. The JSON Schema Validator answers that against a schema you supply, and reports failures per field rather than per character.
Reaching for the wrong one wastes time. If nothing parses, a schema tells you nothing useful. If everything parses but a consumer rejects the payload, a syntax check will report success and leave you no wiser.
What a validator can and cannot tell you
A reported position is where the parser noticed the problem, not always where the problem is. A brace opened on line 4 and never closed is usually reported at the end of the document, because that is where the parser runs out of input. Read a reported line as the start of the search rather than the answer, and work backwards through the structure that encloses it.
Validation is also not repair. Knowing that a comma is missing at line 12 column 3 does not fix the file, and a validator that silently corrected your input would be hiding the very thing you asked it to find. Where a document is close to valid, the JSON Repair tool applies a specific, listed set of fixes and shows you what it changed — so the correction is a decision you make, not one made for you.
Nothing on this page verifies a cryptographic signature. The JWT Decoder shows you the header and payload of a token, which is base64url text that anyone holding the token can read; it does not and cannot tell you whether the token is authentic. Verifying a signature needs the issuer’s key, and a browser tool asking you to paste a signing key would be a worse idea than the convenience is worth.
Nothing is uploaded
Every validator here runs in this tab. The document you are checking, the schema you check it against and the token you decode are all parsed by JavaScript on your device, and no request carries any of it anywhere. That matters more than usual for this group of tools: the payloads people most need to validate are the ones that failed in production, and those are exactly the ones carrying real customer data and real credentials.