JSON Formatter & Validator
Format, validate, and explore JSON data instantly. Your data never leaves your browser.
How to Use This JSON Formatter
Paste your JSON into the editor and click Format to instantly beautify it with proper indentation and line breaks. You can also click Minify to compress it into a single line for use in APIs or configuration files, or Repair to automatically fix common issues like trailing commas, single quotes, unquoted keys, and JavaScript comments.
Use the keyboard shortcut Ctrl+Enter (or Cmd+Enter on Mac) to format instantly without reaching for the mouse. You can also drag and drop a .json file directly onto the editor to load it.
Switch to Tree View to explore your JSON as a collapsible, interactive tree with color-coded types. Use Diff to compare two JSON documents side by side and spot exactly what changed. Or use Convert to transform your JSON into YAML or CSV format instantly.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight data format used to store and exchange information between systems. It is the most common format for API responses, configuration files, and data storage on the web. JSON uses a straightforward structure of key-value pairs and arrays that both humans and computers can read easily.
A typical JSON document looks like this: {"name": "Jane", "age": 28, "active": true}. Keys are always strings wrapped in double quotes, and values can be strings, numbers, booleans, null, arrays, or nested objects. If you are working with web technologies, databases, or APIs, you will encounter JSON regularly.
Features
- Format & Minify — Beautify JSON with customizable indentation (2 or 4 spaces) or compress it to a single line
- Validate — Instant syntax error detection with clear, human-readable messages and line numbers
- Repair — Automatically fix trailing commas, single quotes, unquoted keys, and comments
- Tree View — Explore JSON as a collapsible, color-coded tree with type indicators and item counts
- Diff Comparison — Compare two JSON documents and see additions, deletions, and changes at every level
- Convert to YAML & CSV — Transform JSON into other common formats instantly
- File Upload & Drag-Drop — Load .json files directly from your computer
- Keyboard Shortcuts — Ctrl+Enter to format, Ctrl+Shift+M to minify
Why Use a JSON Formatter?
Raw JSON from APIs and server logs is often minified, meaning it is compressed into a single line with no whitespace. This makes it nearly impossible to read, debug, or understand the data structure at a glance. A JSON formatter adds proper indentation and line breaks so you can quickly scan through the data, identify nested structures, and spot issues.
Beyond readability, a formatter also validates your data. A missing comma or misplaced bracket can break an entire application, and these small errors are notoriously hard to find in unformatted text. This tool highlights exactly where the problem is and describes the issue in plain English, saving you time and frustration.
Privacy and Security
Unlike many online JSON tools that send your data to a remote server for processing, this formatter runs entirely in your browser. Your JSON never leaves your device — not even temporarily. There is no server to intercept your data, no database storing your input, and no third-party service involved. This makes it safe to use with sensitive information like API keys, authentication tokens, database credentials, and internal configuration files.
In late 2025, security researchers discovered that popular JSON formatting sites had been inadvertently exposing user data for years. SudoTool was built with this exact problem in mind: your data stays on your machine, period.