JavaScript Prettifier
About the JavaScript Prettifier
The JavaScript Prettifier formats JavaScript object and array literals to improve readability, automatically applying consistent indentation and spacing so nested data is easy to scan.
This tool is built specifically for data — object and array literals like {name: "John", age: 30} — rather than full programs. It works by evaluating your input as an expression and re-serializing the result with indentation, which means it handles plain data structures well but isn't intended for formatting functions, classes, or complete scripts.
How to Use This Tool
Paste a JS object or array
Enter a JavaScript object or array literal, e.g. {name: "John", age: 30}.
Click "Prettify JavaScript"
The tool reformats it with consistent 4-space indentation.
Copy the result
Use the "Copy" button to grab the formatted output.
Common Use Cases
Reading a Minified Config Object: Paste a compact JS object pulled from a script or console log to see its real structure.
Reviewing Data Pasted from Elsewhere: Clean up an object literal copied from a chat message, ticket, or Stack Overflow answer.
Teaching Object & Array Literal Syntax: Show students a properly indented object structure for a lesson or code review.
Preparing Sample Data for Documentation: Turn a compact object literal into a readable snippet for docs or a tutorial.
Benefits of Using This Tool
Improved Readability
Makes it easier to understand and review object and array data.
Enhances Debugging
Reduces mistakes caused by inconsistently formatted data.
Saves Time & Effort
Skip manually indenting nested objects and arrays.
Instant Processing
Get formatted output within seconds, right in your browser.
Free & Cross-Browser
No installation required — works in all modern browsers.