Free online developer tools that just work

Format and beautify JSON with configurable indentation and optional key sorting. Errors are reported with exact line and column.

Format and beautify messy or minified HTML into clean, indented markup with Prettier, including embedded CSS and JavaScript. Runs locally in your browser.

Format and beautify CSS, SCSS and Less online with Prettier. Turn minified or messy stylesheets into readable, consistently indented code in your browser.

Format and beautify JavaScript and JSX online with Prettier. Choose indentation, quotes, semicolons and line width; your code is formatted in your browser.

Format and beautify TypeScript and TSX online with Prettier, including types, generics and decorators. Choose indentation, quotes and semicolons.

Format and beautify PHP code online in PSR-12 style: braces, spacing, line breaks and 4-space indentation, powered by Prettier PHP. Nothing is uploaded.

Compare two texts or code files online side by side. Additions, deletions and modified lines are highlighted with inline word changes. Runs in your browser.

Compare two JSON documents online, ignoring key order and formatting. Keys are normalised and sorted, so only real changes in values are highlighted.

Run JavaScript online in an isolated browser sandbox. See console output, errors and execution time instantly, with top-level await and stdin input.

Compile and run TypeScript online. Your code is type-checked with the official compiler in strict mode, then runs in a sandboxed worker in your browser.

Run Python 3 code online with the full standard library and stdin input. It runs in your browser with Pyodide (WebAssembly), so your code stays on your device.

Run PHP 8.4 code online and see the output instantly, with stdin input and mbstring. PHP runs in your browser with WebAssembly, so your code stays private.

Compile and run C code online with Clang 21 and stdin input. Your program is compiled to WebAssembly and runs in your browser, so the code stays on your device.

Compile and run C++20 code online with Clang 21, libc++ and stdin input. Programs compile to WebAssembly and run in your browser, so your code stays private.

Convert JSON arrays to CSV online with automatic column detection, nested object flattening and custom delimiters. Open the result in Excel or Sheets.

Convert CSV to a JSON array online with header detection, type inference and delimiter auto-detection. Turn spreadsheet exports into data for APIs and code.

Convert JSON to well-formed XML online with a configurable root element and attribute support. Validate the input and download the XML file.

Convert XML to JSON online, keeping attributes and turning repeated elements into arrays. Malformed XML is reported with its location.

Convert JSON to clean, human-readable YAML online. Turn API responses and package files into config for Kubernetes, Docker Compose or CI pipelines.

Convert YAML documents to formatted JSON online with syntax validation. Errors are reported by line, so broken indentation is quick to find and fix.

Create a professional email signature from ready-made templates, or paste your own HTML. Copy it into Gmail, Outlook or Apple Mail, or download the HTML.

Generate strong, random passwords online with your browser's cryptographically secure generator. Choose length and character sets; check the strength meter.

Generate UUID v4 and time-ordered UUID v7 identifiers (GUIDs) in bulk, with uppercase, hyphen and brace options, using a cryptographically secure generator.

Generate realistic fake test data (names, emails, phones, companies, addresses, IDs and dates) and download it as CSV or Excel (.xlsx). Free, in your browser.

Create free QR codes online for websites and text, with custom size, colours and error correction. Live preview, and download as PNG or SVG.

Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes and HMACs of any text online. Hashing runs in your browser, so the input never leaves your device.

See the current time in any two time zones online, with UTC offsets, the time difference and upcoming daylight saving changes. Compare cities at a glance.

Convert a date and time between time zones online with correct daylight saving handling, including gaps and overlaps. Compare EST, PST, GMT, CET, IST and more.

Convert Unix epoch timestamps in seconds or milliseconds to readable dates and back, in any time zone. See the current Unix time live as it ticks.

Calculate the exact difference between two dates online in years, months, days, hours and business days. Count days until a deadline or since an event.