JSON Validator

A JSON validator checks whether a given string conforms to the JSON specification defined in RFC 8259. It performs a complete json syntax check — verifying that keys and strings use double quotes, commas and colons are placed correctly, brackets and braces are balanced, and every value is a legal JSON type (string, number, object, array, boolean, or null). Think of it as a json lint pass that catches mistakes before they cause runtime errors in your application.

The most frequent JSON errors are small but hard to spot in a wall of text: a trailing comma after the last element, single quotes instead of the required double quotes, an unquoted property name copied from JavaScript, or a missing comma between sibling values. This json checker pinpoints the exact line and character position of the first error, so you can fix it immediately instead of guessing where the parser choked.

Developers reach for a json validator most often when debugging API responses, verifying payloads before sending them to a server, and validating CI/CD configuration files (tsconfig.json, package.json, devcontainer.json) where a single syntax error can break an entire build pipeline. Pasting the suspect JSON into this tool is faster than reading a stack trace and more reliable than eyeballing nested braces.

Beyond pass/fail validation, this tool reports useful document statistics — root type (object or array), total character count, and total key count across all nesting levels. For deeper exploration of valid JSON, try the JSON Tree Viewer; to auto-format it, use the JSON Formatter. All processing happens entirely in your browser via JSON.parse(), so your data never leaves your machine.