Free developer tools
110 quick tools for code, data, images, PDFs and more. They run in your browser, so your files and text stay on your device.
12 tools
HTML Editor
Write HTML and preview it live, with formatting, import and export.
Open toolRegex Tester
Test regular expressions with live highlighting and capture groups.
Open toolRegex Pattern Builder
Assemble a regular expression from building blocks and test it against your text as you go.
Open toolRegex Explainer
Break any regular expression into plain-English pieces, token by token.
Open toolPlain-English Regex Generator
Describe what to match in plain English and get a ready-to-use, tested regex.
Open toolCode Linter
Find syntax errors and common problems in JavaScript, JSON, CSS, HTML and Python.
Open toolCode Diff Generator
Create a unified diff (patch) between two versions of code, ready for git apply.
Open toolCode Comment Generator
Generate JSDoc, Python docstring and PHPDoc blocks from your function signatures.
Open toolJavaScript Minifier
Minify JavaScript with Terser (compress + mangle) or beautify it, and see the bytes saved.
Open toolHTML Formatter
Beautify messy HTML with Prettier or minify it for production.
Open toolSQL Formatter
Format SQL for MySQL, PostgreSQL, SQL Server, SQLite and more, with keyword casing options.
Open toolPerformance Score Calculator
Calculate a Lighthouse-style performance score from your metrics and see what to fix first.
Open tool