JSON Formatter & Validator
Paste your JSON to format, validate, minify, or copy — everything runs in your browser, nothing is uploaded.
JSON Formatter — Beautify and Validate JSON Online
This free JSON formatter instantly beautifies compressed or minified JSON into human-readable, indented format. It also validates your JSON syntax and highlights errors with the exact line number. Paste raw JSON from an API response, config file, or any source — click Format and get clean, readable output in one click.
What Is JSON?
JSON (JavaScript Object Notation) is a lightweight data format used to exchange data between servers and web applications. It is the standard format for REST APIs, configuration files, and data storage in web development. JSON uses key-value pairs, arrays, and nested objects to represent structured data. Well-formatted JSON is critical for debugging, reading API responses, and understanding data structures.
JSON Formatter vs JSON Validator vs JSON Minifier
JSON Formatter (Beautifier): Takes minified or compressed JSON and adds indentation, line breaks, and spacing to make it human-readable. JSON Validator: Checks whether your JSON is syntactically correct — missing commas, unclosed brackets, invalid characters, or wrong data types all cause validation to fail. This tool shows the exact line and character position of the error. JSON Minifier: Removes all whitespace and formatting from JSON to reduce file size. Useful before sending JSON in API requests or storing in production systems.
Common JSON Errors and How to Fix Them
Unexpected token: Usually a missing comma between key-value pairs or array elements. Unexpected end of JSON: A bracket or brace was opened but never closed. Expected string got number: JSON keys must always be quoted strings — {name: "John"} is invalid, {"name": "John"} is correct. Trailing comma: JSON does not allow trailing commas after the last element in an object or array — unlike JavaScript. This formatter detects and reports all of these errors.
JSON Formatter for API Responses
When working with REST APIs, responses often come as compressed single-line JSON. Paste the raw response into this formatter to instantly see the full structure with proper indentation. This is one of the most common developer workflows — it works with responses from any API including REST, GraphQL, weather APIs, payment gateways, social media APIs, and internal microservices.