Web & Dev
The reference material and quick checks that come up while building for the web, and while working out why something cannot reach something else. The IP page is read from the request your browser already made rather than from a third-party lookup, and the subnet calculator does its arithmetic in arbitrary-precision integers so an IPv6 host count is exact rather than rounded. The regex tester runs your pattern inside a worker with a hard timeout, so a catastrophically backtracking expression cannot freeze the tab — a failure mode most online testers still have.
What Is My IP See the public IP address your traffic arrives from, and what it reveals about you. Subnet Calculator Work out network, broadcast, host range, masks and splits for any IPv4 or IPv6 CIDR. Regex Tester Test regular expressions with highlighted matches, capture groups and a safety timeout. Color Converter Convert colors between HEX, RGB, HSL, HWB, OKLCH and CMYK with a live contrast check. HTTP Status Code Lookup Search every HTTP status code with its meaning, typical cause and correct usage. User Agent Parser Break a user agent string into browser, engine, operating system and device. CSS Minifier Minify CSS safely, preserving strings, custom properties and licence comments.