Developer Tools
Handy utilities for building things.
Number Base Converter Enter a value and its base to see it in binary, octal, decimal and hexadecimal at once. Color Converter Enter a colour as HEX, RGB or HSL and see the other formats update instantly, with a live swatch. JSON Formatter & Validator Paste JSON to pretty-print it with indentation, minify it to one line, or check that it's valid. Hash Generator Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text, computed locally in your browser. Unix Timestamp Converter Convert between Unix epoch seconds and readable dates, in both directions, with UTC and ISO output. Regex Tester Test a regular expression against text and see all matches, capture groups and positions live. Base64 Encode & Decode Convert text to and from Base64. Handles Unicode correctly and never sends your data anywhere. JWT Decoder Paste a JWT to read its decoded header and payload, with issued-at and expiry times. HTML Entity Encoder / Decoder Convert text to HTML entities and back, handling reserved characters and numeric entities. URL Encode & Decode Convert text to and from URL percent-encoding, handling spaces, symbols and Unicode. Color Contrast Checker Check the WCAG contrast ratio between two colors, with AA and AAA results for normal and large text. UUID Generator Create random version-4 UUIDs locally, with a choice of how many and one-click copy. Bitwise Calculator Compute bitwise AND, OR, XOR and shifts on two integers, with decimal, hex and binary output. CIDR Subnet Calculator Enter an IPv4 CIDR block to get the network, broadcast, mask, host range and usable host count. Cron Expression Explainer Translate a 5-field cron expression into a plain-English description of when it runs. HMAC Generator Generate an HMAC from a message and secret key with SHA-1, SHA-256, SHA-384 or SHA-512.