Developer Cheatsheets

Quick-reference cards for the formats, patterns, and codes you look up every day. All pages are printable.

Encoders & Converters Cheatsheet

Base64, URL encoding, HTML entities, hex/ASCII reference.

JSON formatting, XML, YAML, regex syntax reference.

SHA, MD5, HMAC, AES key sizes, bcrypt cost factors.

UUID v4 vs v7 vs ULID vs NanoID formats and sizes.

HTTP status codes, headers, CORS, CIDR notation.

Unix timestamps, ISO 8601, cron syntax, timezone offsets.

Common regex patterns for email, URL, phone, date validation.

HEX, RGB, HSL, named colors, WCAG contrast ratios.