Format, validate, and minify JSON payloads with syntax-highlighting, live linting, and export helpers.
Updated Dec 06, 2025
Data Serialization
Debug, format, and minify JSON data directly in your browser. Essential for web development and API integration.
Raw JSON from API responses is often minified and hard to read. This tool expands it with proper indentation and coloring, making it easy to understand the hierarchy.
Collapsible nodes allow you to focus on specific parts of large JSON objects.
Syntax Highlighting
Colors help distinguish keys, strings, numbers, and booleans at a glance.
Error Detection
Quickly identify syntax errors like missing quotes or trailing commas.
Compress your JSON for storage or transmission by removing unnecessary whitespace.
This process reduces payload size without affecting the data's structure or meaning.
Next step
Need to view this data in a spreadsheet? Convert it to CSV format instantly.
Go to JSON to CSVCompare Free JSON Formatter & Validator output with previous revisions to avoid regressions.
Turn sanitized payloads into QR codes for offline reviews.
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write, and easy for machines to parse and generate. JSON is text-based and language-independent, making it ideal for data exchange between servers and web applications.
Raw JSON data often comes as a single line of text without spacing, which is hard to read. A JSON Formatter prettifies this data by adding proper indentation and newlines, making the structure clear and easy to debug. It also validates the JSON syntax to ensure it is error-free.
JSON Minification removes all unnecessary whitespace, newlines, and indentation from the JSON code. This reduces the file size, which is beneficial for storing data or transmitting it over the network, while keeping the data machine-readable.
For many modern web applications, JSON is preferred over XML because it is less verbose (smaller file size), faster to parse, natively supported by JavaScript, and easier to read and write for developers.
Common errors include trailing commas after the last element, using single quotes instead of double quotes, missing quotes around keys, and unclosed brackets or braces. Our tool automatically highlights these errors to help you fix them.
Follow these four quick steps to prepare and validate structured payloads right inside your browser—no downloads, no accounts, and no data leaving the FreeTools.run sandbox.
Step 1: Load your source data
Paste text, drag a file, or start with our curated sample to understand how the formatter workflow behaves with real inputs.
Step 2: Adjust tool options
Toggle presets, update formatting rules, or choose export preferences. All controls update in real time so you can preview the effect before committing.
Step 3: Review the live preview
Use the split-pane preview, inline validation, or diff output to confirm the transformation looks correct before you copy anything back into your project.
Step 4: Export or chain another tool
Copy the result, download a file, or jump into a related FreeTools.run utility (like Diff Checker or the QR Code Generator) to continue the workflow without leaving the browser.
