dev-tool-x

JSON Validator

Input

Validate JSON and show parse errors.

Output

About JSON Validator
JSON Validator parses a JSON document and reports any syntax errors with the line and column number where the problem was found. It uses the same parser that production environments use, so a document that passes here will parse correctly in your application. Use it to check a hand-edited config file before deploying, validate an API response before wiring it into your data model, or quickly confirm that a pasted snippet is well-formed before including it in a test fixture.
Common uses
  • Check JSON syntax before consuming data in an application, script, or deployment pipeline.
  • Get a clear error message with line and column info when an API response or config file fails to parse.
  • Validate hand-edited files after making changes to catch typos and structural mistakes early.
  • Keep validation local in the browser while working with sensitive or temporary developer data.
Related tools
JSON FormatterFormat and validate JSON with readable indentation.JSON ViewerPretty-print JSON for inspection.JSON ParserParse JSON and normalize it as formatted output.JSON MinifyCompact JSON into one line.
FAQ
What errors does JSON Validator catch?
The validator checks for all JSON syntax errors: mismatched tags or brackets, missing commas or colons, unquoted keys, invalid escape sequences, and structural problems. It reports the line and column number of the first error found so you can navigate directly to the problem.
Does it validate schema as well as syntax?
The tool checks syntax only — whether the document is structurally valid JSON. It does not check whether the document conforms to a specific schema (e.g. JSON Schema, XSD, or OpenAPI). For schema validation, use a schema-aware tool or library in your application.
Why is my document showing as invalid when it works in my app?
Some parsers are lenient and accept documents with minor syntax errors like trailing commas or comments. The tool uses a strict parser that follows the specification precisely. If your document works in a lenient parser but fails here, it is technically invalid and may behave unexpectedly in stricter environments.
Is JSON Validator free to use?
Yes — JSON Validator is completely free and requires no sign-up or account. There are no usage limits for standard validator tasks.
Does JSON Validator send my data to a server?
No. JSON Validator runs entirely in your browser using JavaScript. Text you paste and files you upload never leave your machine, so it is safe to use with sensitive payloads, API tokens, and internal configuration data.