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JSON Formatter

Format / minify / validate JSON — configurable indent, precise error location, one-click copy

Indent
Input JSONJSON
Lines: 0Chars: 0
OutputJSON
Lines: 0Chars: 0

Overview: JSON Formatter is a professional online tool for formatting, minifying and validating JSON. It helps developers beautify messy JSON strings, collapse them into a single line to save bandwidth, or instantly locate syntax errors while editing. Under the hood it uses the browser’s native JSON.parse and JSON.stringify for fast, highly compatible parsing that strictly conforms to ECMA-404 and RFC 8259.

How to use: Step 1 — paste or type the JSON you want to process into the left editor, or click the "Sample" button to load a built-in example. Step 2 — pick the indent style in the top-right toolbar (2 spaces, 4 spaces or a Tab); the result is regenerated on the fly. Step 3 — click "Minify" to collapse the JSON into a single compact line, ideal for embedding in code or sending as an API request body. Step 4 — the right panel supports one-click copy and downloading as a .json file. If the JSON has a syntax error, an inline hint with the exact location and message is shown below the input to help you pinpoint the problem quickly.

Typical scenarios: Back-end developers debugging RESTful API responses can paste the payload here to inspect its structure. Front-end developers working on configuration files such as package.json or tsconfig.json can normalise formatting and keep their team style consistent. QA engineers writing API test cases can minify JSON before dropping it into scripts to avoid escape headaches. Data analysts can format log or tracking data to visualise nested fields more easily.

Technical notes: This tool follows the strict JSON specification and does not support JSON5 extensions such as comments, single quotes or trailing commas. Keys must use double quotes; special characters inside strings must be escaped with \; numbers may be integers, floats or scientific notation; booleans are exactly true/false, and the null value is null. For very large files (tens of MB or more) we recommend using a desktop streaming parser to avoid browser lag.

Privacy: All parsing, formatting and minifying happen locally in your browser. The JSON you enter is never uploaded to any server or written to any log, so you can safely process business data that contains sensitive information.

Frequently Asked Questions

How do I use JSON Formatter?
Step 2 — pick the indent style in the top-right toolbar (2 spaces, 4 spaces or a Tab); the result is regenerated on the fly. Step 3 — click "Minify" to collapse the JSON into a single compact line, ideal for embedding in code or sending as an API request body.
What can JSON Formatter do?
Front-end developers working on configuration files such as package.json or tsconfig.json can normalise formatting and keep their team style consistent. QA engineers writing API test cases can minify JSON before dropping it into scripts to avoid escape headaches.
Is my data private when I use JSON Formatter?
The JSON you enter is never uploaded to any server or written to any log, so you can safely process business data that contains sensitive information. The JSON you enter is never uploaded to any server or written to any log, so you can safely process business data that contains sensitive information.
What technical details should I know about JSON Formatter?
Keys must use double quotes; special characters inside strings must be escaped with \\ ; numbers may be integers, floats or scientific notation; booleans are exactly true / false , and the null value is null . For very large files (tens of MB or more) we recommend using a desktop streaming parser to avoid browser lag.