Web & developer files

HTTP status codes, MIME types, file extensions, HTML entities and CSS units for developers.

• ASCII printable characters Full ASCII table with decimal, hex and binary codes, control-character names, and printable symbols — look up any character code instantly online.
• Common MIME types Content-Type values for web pages, documents, images, audio, and video — with the file extensions they usually pair with. Pick the right header every time.
• CSS size units (px rem em vh) When to use px, rem, em, %, vw/vh and other CSS length units — quick guidance on each. Pick the right CSS unit for your next layout in seconds.
• Common file extensions What popular file extensions usually mean on the desktop and the web — from .pdf and .zip to .exe and .svg. Identify any file instantly at a glance.
• HTML character entities Common HTML entities for symbols, punctuation, and whitespace, with their entity names. Copy the code you need without hunting through reference tables.
• HTTP status codes quick reference Common HTTP response status codes with short, plain-English meanings for 200, 404, 500 and more. A quick reference for API development and debugging.
• Number bases (decimal hex binary) Convert decimal, hexadecimal, binary and octal instantly — full 0–32 chart, bit basics, and 0x/0b prefixes for programmers, students and engineers.