JSON Formatter & Validator
Free online JSON formatter and validator. Beautify, minify, and validate JSON with line-accurate error messages. Sort keys, escape strings, and copy results instantly.
Why developers reach for a JSON validator
APIs, config files, and webhook payloads all rely on well-formed JSON. A single misplaced comma can break an entire deploy pipeline. Validating JSON before shipping helps you catch malformed quotes, trailing commas, unclosed brackets, and duplicate keys.
Beautified JSON is easier to scan in pull request reviews. Minified JSON is smaller over the wire and reduces bandwidth. Sorting keys alphabetically makes two semantically identical payloads diff cleanly when their keys were originally in different orders.
Common JSON errors and how to fix them
- Trailing commas: JSON does not allow a comma after the last element. Remove the final comma in arrays and objects.
- Single quotes: JSON requires double quotes for both keys and strings. Replace
'with". - Unquoted keys: Unlike JavaScript object literals, JSON keys must be quoted strings.
- Comments: JSON does not support
//or/* */comments. Strip them before parsing. - NaN, Infinity, undefined: These are not valid JSON values. Use
nullor numeric replacements.
Privacy first
All parsing and formatting happens locally in your browser. Your JSON payload never touches our servers, which makes this tool safe to use for sensitive API responses, internal config, or test fixtures.