JSON Validator

About the JSON Validator

The JSON Validator checks whether a piece of text is syntactically valid JSON according to the official ECMA-404 specification. Invalid JSON is one of the most common causes of broken API integrations, failed deployments, and runtime errors in modern applications — this tool tells you exactly where the problem is so you can fix it in seconds instead of hours.

What the validator detects

Missing commas between elements, trailing commas (not allowed in strict JSON), unquoted keys, single quotes instead of double quotes, unescaped newlines or tabs inside strings, mismatched braces and brackets, invalid Unicode escape sequences, comments (also not allowed in strict JSON), and BOM characters that confuse parsers. For each error, the line and column number are reported so you can jump straight to the issue.

How to use it

1. Paste your JSON into the input area — an API response, a config file, anything.
2. Click Validate or watch the live validation indicator update as you type.
3. If valid: a green confirmation appears. If invalid: the exact line and reason are shown.

Why validation matters

A single misplaced comma can crash an entire API integration. Validating before deploying configuration changes, before sending API payloads, before importing fixture data into databases, and before publishing JSON-LD schema markup saves enormous amounts of debugging time. The validator is especially useful when working with hand-written JSON or JSON that has been concatenated programmatically.

Privacy

Validation runs entirely in your browser using a native JSON parser. Your data is never sent to our servers or stored anywhere. You can safely validate API keys, credentials, internal configs, or any other sensitive JSON content.

Tamer Baghdadi

CEO / Co-Founder