A code formatter automatically reformats source code to a consistent style, eliminating indentation inconsistencies, mixed quotes, and line length violations. This tool uses Prettier, the industry-standard formatter trusted by millions of developers, running directly in your browser.
Input
Output
How to Use the Code Formatter
The code formatter uses Prettier — the most popular opinionated code formatter — to automatically reformat source code in your browser. No installation required. Prettier enforces consistent style by reprinting code from its AST (Abstract Syntax Tree), so the output always looks the same regardless of how the original was indented.
Step 1: Select a Language
Choose your language from the dropdown: JavaScript, TypeScript, HTML, CSS, JSON, Markdown, or YAML. The correct Prettier parser plugin is loaded automatically. Note that the formatter loads Prettier's plugins from a CDN on first use — this takes a moment on the first format.
Step 2: Configure Options
Adjust the formatting options to match your project's style guide: Tab width (2 or 4 spaces), Quote style (single or double quotes), Semicolons (required or optional), Trailing commas (all, es5-safe, or none), and Print width (maximum line length before Prettier wraps).
Step 3: Paste and Format
Paste your code into the Input panel and click Format with Prettier. The formatted output appears in the right panel. If your code has syntax errors, Prettier will display an error message — fix the syntax first, then reformat. Click Copy to copy the formatted output to your clipboard.
What Prettier Does (and Doesn't) Change
Prettier reformats the code's style — indentation, line breaks, quote style, and spacing — but never changes what your code actually does. Variable names, logic, and structure stay exactly the same. It is safe to run Prettier on any code without changing its behavior.
FAQ
Is this code formatter free to use?
Yes, the code formatter is completely free with no usage limits and no account required. Format as much code as you need — all processing happens in your browser.
Is my code safe and private?
Yes. The formatter runs entirely client-side using Prettier's WebAssembly build loaded from a CDN. Your code is never sent to any server, never stored, and never logged.
What languages does the formatter support?
The formatter supports JavaScript, TypeScript, HTML, CSS/SCSS/Less, JSON, Markdown, and YAML. It uses Prettier's official parser plugins for each language, so the output matches what you would get from running Prettier locally.
What is Prettier and why use it?
Prettier is the most widely used opinionated code formatter. It parses your code and reprints it from scratch using consistent style rules, eliminating style debates in teams and making code reviews faster. It supports 15+ languages and integrates with all major editors.
How do I format TypeScript code?
Select 'TypeScript' from the language dropdown, paste your TypeScript code, and click Format. The formatter handles all TypeScript-specific syntax including type annotations, interfaces, generics, and decorators using Prettier's official TypeScript plugin.
Can I change the indentation and quote style?
Yes. Use the options panel below the language selector to configure tab width (2 or 4 spaces), quote style (single or double), semicolons (on or off), trailing commas (all, es5, or none), and print width (80, 100, or 120 columns).
What happens if my code has a syntax error?
Prettier will show a formatting error message below the editor describing the syntax problem it encountered. Fix the syntax error in your code and reformat — the formatter cannot output valid code if the input has syntax errors.