Code Formatter & Beautifier

About This Tool

A powerful online code formatter that supports multiple programming languages including JavaScript, TypeScript, Python, JSON, HTML, CSS, XML, YAML, and Markdown. Simply paste your code or upload a file, select your language, and get beautifully formatted code instantly.

NinjaFunction's Code Formatter & Beautifier is a powerful online tool that takes messy, minified, or inconsistently indented source code and transforms it into clean, readable, properly formatted code — right in your browser, without uploading a single byte to any server. It supports a wide range of programming and markup languages including JavaScript, TypeScript, Python, JSON, HTML, CSS, SCSS, XML, YAML, Markdown, SQL, and more, so whether you're a frontend developer wrestling with a tangled React component, a backend engineer cleaning up a Python script, a data analyst formatting a JSON payload from an API, or a technical writer beautifying Markdown documentation, this tool handles it all in one place. Simply paste your code into the input area — or drag and drop a file directly onto the page — select the language from the dropdown, and the formatter instantly produces a beautifully indented, consistently spaced version of your code that follows the conventions of that language. If you don't know which language your snippet is in, the auto-detect option will make an educated guess based on syntax patterns, saving you a click. The tool doesn't just add indentation; it also normalizes spacing around operators, aligns object properties and array elements, breaks long lines sensibly, removes trailing whitespace, converts tabs to spaces (or vice versa, based on your preference), sorts imports and keys where appropriate, and standardizes quote styles for languages that support both single and double quotes. Formatting code is one of those chores that feels trivial until you actually sit down to do it manually — sorting out brace alignment in a 500-line JavaScript file by hand can eat twenty minutes of your day, and the odds of introducing a typo while re-indenting are surprisingly high. This tool eliminates that entirely by applying well-tested formatting rules in milliseconds. It also serves a critical role in code review: nothing slows down a pull request faster than a diff polluted with indentation changes that obscure the actual logic changes. Pre-formatting code before committing keeps diffs clean and makes the reviewer's job manageable. Similarly, when you're copying code from a blog post, a Stack Overflow answer, an email, or a PDF, the formatting almost never comes through cleanly — leading spaces get eaten, indentation collapses, and what was once readable code becomes a jumbled wall of text. Running it through this formatter restores the structure instantly. The tool is especially useful for JSON, which is notoriously unforgiving of stray commas, mismatched braces, and invalid escapes, but which is also the data format of the modern web — every REST API, every configuration file, every NoSQL database uses JSON. Beautifying JSON in this tool produces nicely indented, line-broken output that you can paste directly into documentation or config files, and any syntax error is reported with a line and column number so you can track it down in seconds. For HTML and CSS, the formatter respects the nesting structure of markup and stylesheets, producing output that reflects the visual hierarchy of the page. For Python, it applies PEP 8-inspired conventions including four-space indentation and consistent spacing around operators. For JavaScript and TypeScript, it follows widely adopted community conventions similar to those used by Prettier, making the output feel familiar to anyone who has worked with modern JS toolchains. The formatter is also deeply useful for legacy code: if you've inherited a codebase that was written years ago by multiple authors using different editors and styles, running it through a formatter is often the first step toward modernizing it. Getting everything into a consistent shape makes the code easier to read, easier to grep through, and easier to review in future diffs. Because the tool runs entirely in your browser using client-side JavaScript, it is safe for proprietary code, internal scripts, client work, and anything else you wouldn't want to send to a random third-party server — a real concern when using free online formatters, many of which log or analyze what you paste. Nothing you type is transmitted to our servers, nothing is stored, and nothing is analyzed. You can verify this by opening your browser's Developer Tools and watching the Network tab — no requests fire when you format code. Once the page has loaded, the tool works fully offline, so you can even use it on a plane or in a secure environment without internet access. Output can be copied to your clipboard with one click, or downloaded as a file if you prefer to save the formatted result. Formatting preferences are respected — you can choose between two, four, or eight spaces for indentation, or use tabs, and toggle options like sorting keys, removing comments, or collapsing blank lines to match your team's style guide. For developers who frequently work across multiple languages in the same project — a typical full-stack app, for example, might involve TypeScript on the frontend, Python or Node.js on the backend, JSON for API payloads, YAML for CI/CD config, and Markdown for documentation — having one reliable formatter that handles all of them saves you from juggling half a dozen specialized tools with different interfaces and different quirks. Whether you're debugging a minified JavaScript bundle by expanding it back into readable form, cleaning up a JSON response from an API, preparing code to paste into a blog post or tutorial, verifying that a configuration file is valid before deployment, or simply trying to make sense of code someone else wrote, NinjaFunction's Code Formatter & Beautifier gives you clean, consistent, professionally formatted output in a fraction of a second — free, private, and available anywhere you have a browser.