Free, comprehensive quick-reference guides for everyday development. Bookmark the ones you use most.
A comprehensive regular expression reference covering character classes, quantifiers, anchors, groups, lookaheads, common patterns, and flags. Bookmark this page for quick regex lookups while coding.
Essential Git commands for everyday development. Covers setup, branching, merging, rebasing, remote operations, stashing, undoing changes, and viewing history. A must-have reference for any developer using Git.
Quick reference for HTML elements and attributes. Includes document structure, text formatting, links, media, lists, tables, forms, semantic elements, and essential meta tags for SEO and social sharing.
Complete CSS reference covering selectors, the box model, Flexbox, Grid, typography, colors, transitions, animations, and media queries. Everything you need to style modern, responsive websites.
Essential JavaScript reference covering variables, types, strings, arrays, objects, functions, DOM manipulation, promises, async/await, and modern ES6+ features. Perfect for quick lookups during development.
A quick reference for TypeScript covering basic types, interfaces, generics, utility types, type guards, and module declarations. Keep this handy while writing type-safe code.
Essential Python reference covering data types, string methods, list comprehensions, dictionary operations, file I/O, and common built-in functions. A quick lookup for everyday Python programming.
Quick SQL reference covering SELECT queries, filtering, joins, aggregation, data manipulation, and schema operations. Useful for writing queries across MySQL, PostgreSQL, SQLite, and other databases.
Complete Markdown syntax reference covering headings, text formatting, links, images, lists, code blocks, tables, and extended syntax like footnotes and task lists.
Essential Bash and shell scripting reference covering file operations, text processing, variables, loops, conditionals, permissions, and networking commands.
Docker quick reference covering container management, images, volumes, networks, Docker Compose, Dockerfile instructions, and debugging techniques.
Tailwind CSS utility class reference covering layout, flexbox, grid, spacing, typography, colors, backgrounds, responsive design, and state variants.
A complete HTTP status codes reference covering 1xx through 5xx, what each code means, when APIs return them, and how to debug common errors.
A practical cron cheat sheet covering syntax, field values, special characters, and ready-to-use expressions for common scheduling patterns.
A quick reference for Linux file permissions, chmod numeric and symbolic modes, common permission sets, and when to use each one.
A quick reference for JSON syntax rules, supported data types, formatting conventions, and the most common mistakes that cause parsing errors.
A quick reference for all CSS length units — absolute and relative — with clear guidance on when to use px, rem, em, vw, vh, ch, and more.