Free Developer Tools Online — JSON, Base64, URL & More

Essential utilities for developers — format and validate JSON, encode/decode Base64 and URLs, look up DNS records, and more. All free, all private, all in your browser.

JSON Formatter Format, validate, and minify JSON. URL Encoder / Decoder Percent-encode and decode URL strings. Base64 Encoder / Decoder Encode text to Base64 or decode it back. DNS Lookup Query A, AAAA, MX, TXT, CNAME, and NS records. Color Converter Convert colors between HEX, RGB, HSL, and HSV formats. Hash Generator Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from text. UUID Generator Generate random UUID v4 identifiers for development and testing. Timestamp Converter Convert Unix timestamps to human-readable dates and vice versa. CSS Minifier Minify and compress CSS code to reduce file size. Regex Tester Test regular expressions against sample text with live match highlighting. Number Base Converter Convert numbers between binary, octal, decimal, and hexadecimal. Text to Binary Convert text to binary (ASCII) representation and back. Chmod Calculator Convert Unix file permissions between numeric (755) and symbolic (rwxr-xr-x) forms. Text to Hex Converter Convert text to hexadecimal and decode hex back to readable text. JWT Decoder Decode and inspect a JSON Web Token's header, payload, and signature. Cron Expression Generator Build and explain cron schedules with next run times. CSS Gradient Generator Visually build linear and radial CSS gradients and copy the code. HTML Entity Encoder / Decoder Encode and decode HTML special characters like &, <, >, and quotes. Image to Base64 Convert an image to a Base64 data URI for HTML, CSS, or email. XML Formatter Format, validate, and pretty-print XML documents in the browser. HTML Formatter Indent and prettify HTML markup instantly in the browser. SQL Formatter Format, beautify, and minify SQL for MySQL, PostgreSQL, and SQL Server. Favicon Generator Generate favicons from text or an image in every size, plus favicon.ico. CSS Box Shadow Generator Build box-shadow code visually with offset, blur, spread, and layers. Color Contrast Checker Test text and background colors against WCAG AA and AAA standards. CSS Border Radius Generator Build border-radius code visually with per-corner sliders and a live preview. IP Subnet Calculator Get network, broadcast, host range, and masks from any IPv4 CIDR. PX to REM Converter Convert px, rem, and em with a custom root size and a live table. Color Palette Generator Harmonious palettes from any base color with HEX, RGB, and HSL codes. Text Encryption / Decryption Encrypt and decrypt text with a password using AES-256-GCM. CSS Flexbox Generator Build a flexbox layout visually and copy the container CSS. Cubic Bezier Easing Generator Design custom CSS animation easing curves and copy cubic-bezier().