Paste your JSON to format, validate, minify, and beautify instantly. 100% client-side — your data never leaves your browser.
JSON (JavaScript Object Notation) is a data format widely used in APIs, configuration files, and databases. Raw JSON from APIs is often minified (no spaces/newlines) making it unreadable. JSON formatting adds proper indentation and line breaks, transforming a single long line like {"name":"John","age":30} into a clearly readable, hierarchical structure. This makes debugging APIs, reviewing configurations, and understanding data structures much easier.
The validator uses JavaScript's built-in JSON.parse() function to attempt parsing your JSON. If it parses successfully, the JSON is valid. If not, it returns an error with the position in the string where parsing failed. Common JSON errors include: trailing commas (not allowed in standard JSON), single quotes instead of double quotes around strings, missing commas between array items, and unescaped special characters in strings.
Yes. This tool is 100% client-side — all formatting and validation happens in your browser using JavaScript. No data is sent to any server. Even if you close the browser tab, no trace of your JSON is stored anywhere. This makes it safe to use with API responses containing authentication tokens, user data, or other sensitive information. You can verify this by checking the browser's network tab — there are zero outbound requests.
JSON minification removes all unnecessary whitespace (spaces, tabs, newlines) from JSON, reducing its file size. This is useful for: reducing API response payload sizes, embedding JSON in code where whitespace is unnecessary, comparing two JSON strings character by character, and optimizing config files. A typical formatted JSON can be 20–40% larger than its minified equivalent. For production APIs, always send minified JSON to reduce bandwidth.
Standard JSON (ECMA-404) is strict: string keys must be double-quoted, no trailing commas, no comments, no single-quoted strings. JSON5 is a superset that allows comments (// and /* */), trailing commas, single-quoted strings, and unquoted keys (if they are valid identifiers). JSON5 is used in some configuration formats like .json5 files, but standard web APIs use strict JSON. This formatter handles standard JSON only.