Dev Reference
Crontab, chmod, MIME types, HTTP headers
ASCII Table
Full ASCII table with decimal, hexadecimal, octal and character.
Bank Account Generator
Generate fake Brazilian bank account numbers for testing. Major banks included.
CEP Generator
Generate random valid-format Brazilian CEPs for testing. Filter by state.
chmod Calculator
Free online chmod calculator. Convert Linux file permissions between octal (755) and symbolic (rwxr-xr-x) notation.
CNPJ Generator & Validator
Generate and validate numeric and alphanumeric CNPJs (new 2026 format). Official algorithm with check digits.
Color Contrast Checker
Check color accessibility according to WCAG 2.0 guidelines.
CPF Generator
Generate and validate CPF numbers online. Official algorithm with two check digits.
Test Credit Card Number Generator
Generate valid test credit card numbers using the Luhn algorithm for development. Supports Visa, Mastercard, and Amex.
Crontab Expression Parser
Free online crontab parser. Convert cron expressions to human-readable descriptions with presets for common schedules.
CSS Selectors Reference
Complete reference of CSS selectors with examples.
Docker Cheatsheet
Quick reference of Docker commands with search and category filter.
Git Commands Cheatsheet
Free Git commands cheatsheet. Categorized reference with descriptions, examples, and common workflows.
HTML Colors Reference
Complete reference of all 140+ named CSS/HTML colors with hex codes, RGB values, and live preview.
HTML Entities Table
HTML entities reference with name, number and character.
HTTP Status Codes Reference
Complete reference of all HTTP status codes with descriptions. Search by code, name, or description.
JavaScript Array Methods
Complete reference of JavaScript Array methods with examples.
Keyboard Shortcuts Reference
Free keyboard shortcuts cheatsheet for VS Code, Chrome, Windows, and Mac. Search and copy hotkeys instantly.
Linux Cheatsheet
Quick reference of Linux/Unix commands with search.
MIME Types Reference
Searchable reference table of file extensions and MIME content types. Find the right Content-Type for any file.
Python Cheatsheet
Quick reference of Python syntax and patterns.
Regex Cheatsheet
Quick reference of regular expressions with examples.
SQL Cheatsheet
Quick reference of SQL commands with examples.
Tailwind CSS Cheatsheet
Quick reference of Tailwind CSS classes with CSS equivalent.