Free Online Developer Tools
Free online developer tools: JSON formatter and validator, code formatter, diff checker, Base64 and URL encoders, JWT decoder, regex tester, hash generator and more. All run in your browser.
Available now
JSON Editor Two panels with text, tree and table modes, compare, transform and repair JSON Formatter Pretty print messy JSON with your preferred indentation JSON Validator Find the exact line and character of any JSON syntax error JSON Minifier Strip whitespace to shrink JSON for production Code Formatter Beautify JavaScript, TypeScript, CSS, HTML and SQL Text Diff Checker Compare two texts and highlight every difference XML Formatter Pretty print and validate XML, SVG and XHTML Base64 Encode / Decode Encode text or files to Base64 and back URL Encode / Decode Percent-encode or decode URLs and query strings JWT Decoder Inspect JWT header, payload and expiry without a server Regex Tester Live-match regular expressions with group highlighting UUID Generator Generate one or thousands of v4 UUIDs Hash Generator Hash text or files with MD5, SHA-1, SHA-256 and SHA-512 HTML Entity Encoder Escape and unescape HTML entities safely Cron Expression Parser Translate cron schedules into plain English and next run times SQL Formatter Format SQL for MySQL, PostgreSQL, SQLite and SQL Server GraphQL Formatter Format and validate GraphQL queries and schemas Mock JSON Generator Generate realistic fake JSON from a simple schema API Request Tester Send GET, POST and other requests and inspect the response Password Generator Strong random passwords and passphrases, generated locally
Frequently asked questions
Are these developer tools really free?
Yes. Every tool on Cuisdev is free with no sign-up, no usage caps and no watermarks.
Is my code or data uploaded to a server?
No. All processing happens in your browser using JavaScript and WebAssembly. Nothing you paste or drop is sent anywhere.
Can I use these tools offline?
Once a tool page has loaded it keeps working without a connection, and the site can be installed as an app for offline use.