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CSS Flexbox: The Complete Visual Guide
web-development

CSS Flexbox: The Complete Visual Guide

Master Flexbox layout — align, justify, wrap, grow, shrink, and order with visual examples for every property.

Core Web Vitals: LCP, INP, CLS Explained
web-development

Core Web Vitals: LCP, INP, CLS Explained

Understand Google's Core Web Vitals — what LCP, INP, and CLS measure, good scores, and how to improve each one.

DNS Records Explained: A, CNAME, MX, TXT, and More
devops

DNS Records Explained: A, CNAME, MX, TXT, and More

Understand DNS records — what each type does, when to use them, and how to debug DNS issues.

npm vs yarn vs pnpm: Which Package Manager in 2026?
web-development

npm vs yarn vs pnpm: Which Package Manager in 2026?

Compare npm, yarn, and pnpm — speed, disk usage, monorepo support, and which one to pick for your project.

TypeScript Utility Types: The Practical Cheatsheet
web-development

TypeScript Utility Types: The Practical Cheatsheet

Master Partial, Pick, Omit, Record, Required, and more — with real use cases, not just definitions.

SSH Keys: Generate, Configure, and Manage Like a Pro
devops

SSH Keys: Generate, Configure, and Manage Like a Pro

Set up SSH keys for GitHub, servers, and multiple accounts — Ed25519, ssh-agent, and the config file.

REST API Design: Naming, Pagination, Errors, and Versioning
web-development

REST API Design: Naming, Pagination, Errors, and Versioning

Design APIs that developers actually enjoy using — resource naming, pagination patterns, error formats, and versioning strategies.

CORS Explained: Why Your API Call Is Blocked
web-development

CORS Explained: Why Your API Call Is Blocked

Understand CORS errors once and for all — what the browser is doing, why preflight requests exist, and how to fix it.

How to Format JSON: Complete Guide
formatting

How to Format JSON: Complete Guide

Learn the best practices for formatting, validating, and minifying JSON data in your daily workflow.

SQL Formatting Best Practices for Readable Queries
formatting

SQL Formatting Best Practices for Readable Queries

Write clean, maintainable SQL with proper formatting conventions that your whole team can follow.

Git Branching Strategies: Gitflow vs Trunk-Based vs GitHub Flow
devops

Git Branching Strategies: Gitflow vs Trunk-Based vs GitHub Flow

Choose the right branching strategy for your team — comparing Gitflow, trunk-based development, and GitHub Flow.

TOTP: How Two-Factor Authentication Actually Works
security

TOTP: How Two-Factor Authentication Actually Works

The math behind those 6-digit codes from Google Authenticator — HMAC, time steps, and implementing TOTP from scratch.

JSON to CSV: Convert Data for Spreadsheets
converting

JSON to CSV: Convert Data for Spreadsheets

Export API data to CSV format for Excel, Google Sheets, or data analysis tools.

Open Graph Meta Tags: Control How Your Links Look on Social Media
web-development

Open Graph Meta Tags: Control How Your Links Look on Social Media

Set og:title, og:image, og:description and Twitter Cards to make your links stand out when shared.

UUID v4: Why and How to Generate Unique IDs
generating

UUID v4: Why and How to Generate Unique IDs

Understanding UUID generation, collision probability, and when to use them in your systems.

Zodiac Signs Calculator: Find Your Sign by Birth Date
date-time

Zodiac Signs Calculator: Find Your Sign by Birth Date

Find your zodiac sign instantly by entering your birth date. Learn about all 12 signs, their date ranges, and characteristics.

Docker Commands: The Complete Cheatsheet
cheatsheets

Docker Commands: The Complete Cheatsheet

Every Docker command you need, organized by category — from containers to compose to system cleanup.

Dockerfile Best Practices: Smaller, Faster Builds
devops

Dockerfile Best Practices: Smaller, Faster Builds

Write production-ready Dockerfiles — multi-stage builds, layer caching, security hardening, and image size optimization.

bcrypt: The Best Way to Hash Passwords
security

bcrypt: The Best Way to Hash Passwords

Why bcrypt remains the gold standard for password hashing, and how to implement it correctly.

Markdown Syntax: The Complete Cheatsheet
productivity

Markdown Syntax: The Complete Cheatsheet

Every Markdown feature in one place — headings, links, images, tables, code blocks, and GitHub-flavored extras.

Environment Variables: The Developer's Guide
devops

Environment Variables: The Developer's Guide

Manage configuration properly — .env files, process.env, secrets in CI/CD, and the 12-factor app approach.

Color Contrast: WCAG Accessibility Guide
web-development

Color Contrast: WCAG Accessibility Guide

Check if your color combinations meet WCAG accessibility standards — and why it matters more than you think.

Password Generator: How to Create Truly Strong Passwords
security

Password Generator: How to Create Truly Strong Passwords

The math behind password strength, why length beats complexity, and how to generate secure passwords.

HTTP Status Codes: The Complete Reference
web-development

HTTP Status Codes: The Complete Reference

Every HTTP status code explained — when to use 200 vs 201, why 404 isn't always a mistake, and what 503 means for your users.

Brazil's Minimum Wage: History, Values, and Calculator
finance

Brazil's Minimum Wage: History, Values, and Calculator

Track Brazil's minimum wage history from 1940 to 2026. Calculate purchasing power changes and understand the annual adjustment policy.

Regex Patterns: The Ultimate Reference
cheatsheets

Regex Patterns: The Ultimate Reference

Common regex patterns with explanations, from email validation to password rules to URL parsing.

.gitignore Patterns: What to Exclude from Your Repository
devops

.gitignore Patterns: What to Exclude from Your Repository

Write effective .gitignore files — patterns, common templates, and the files you should never commit.

URL Encoding: Why %20 Appears in Your URLs
web-development

URL Encoding: Why %20 Appears in Your URLs

Understand URL encoding — which characters need escaping, why browsers do it, and how to encode/decode properly.

Cron Expressions: Schedule Tasks Like a Pro
devops

Cron Expressions: Schedule Tasks Like a Pro

Master cron syntax for automated task scheduling — from basics to advanced patterns.

Base64 Encoding: What It Is and How to Use It
encoding

Base64 Encoding: What It Is and How to Use It

Everything you need to know about Base64 — encoding, decoding, data URIs, and when NOT to use it.

SHA-256 Hashing: How It Works and When to Use It
security

SHA-256 Hashing: How It Works and When to Use It

Understand SHA-256 hashing — how it produces fixed-length digests, why it's irreversible, and where it's used in real systems.

Spinner Wheel: Make Random Decisions the Fun Way
fun

Spinner Wheel: Make Random Decisions the Fun Way

Create custom spinner wheels for random selection. Perfect for classrooms, team decisions, giveaways, and breaking deadlocks.

CSS Minification: A Performance Quick Win
formatting

CSS Minification: A Performance Quick Win

Compress your CSS files for faster page loads — what gets removed, how much you save, and when it matters.

JWT Tokens: Decode and Understand Your Tokens
security

JWT Tokens: Decode and Understand Your Tokens

Inspect JWT tokens to debug authentication issues — understand the header, payload, and signature.

Linux Terminal: 50 Essential Commands
cheatsheets

Linux Terminal: 50 Essential Commands

The most used Linux commands for developers and sysadmins — organized by category with real examples.

First Million Calculator: How Long to Reach Your Goal?
finance

First Million Calculator: How Long to Reach Your Goal?

Find out how long it takes to save your first million with different investment strategies. Realistic scenarios with compound interest.

CPF and CNPJ Generator: Valid Numbers for Testing
dev-reference

CPF and CNPJ Generator: Valid Numbers for Testing

Generate valid CPF and CNPJ numbers for software testing. Understand the validation algorithm and why test data matters.

Savings Simulator: The Power of Compound Interest
finance

Savings Simulator: The Power of Compound Interest

Simulate your savings growth with compound interest. See how regular contributions and time can build wealth.

Fraction Calculator: Add, Subtract, Multiply, and Divide Fractions
finance

Fraction Calculator: Add, Subtract, Multiply, and Divide Fractions

Master fraction arithmetic with step-by-step explanations. Calculate with fractions, mixed numbers, and simplify results instantly.

List Sorter: Organize Text Lists Alphabetically or Numerically
text

List Sorter: Organize Text Lists Alphabetically or Numerically

Sort any text list alphabetically, numerically, or in reverse order. Remove duplicates and clean up messy lists instantly.

Rule of Three Calculator: Solve Proportions Instantly
finance

Rule of Three Calculator: Solve Proportions Instantly

Learn how to use the rule of three to solve proportions in everyday life, cooking, finance, and programming.

WhatsApp Link Generator: Create Click-to-Chat Links
generators

WhatsApp Link Generator: Create Click-to-Chat Links

Generate WhatsApp click-to-chat links for your business. Let customers message you directly without saving your number first.

Receipt Generator: Create Professional Receipts Online
documents

Receipt Generator: Create Professional Receipts Online

Generate professional receipts for payments, services, and freelance work. No software needed, create and download instantly.

Online Notepad: Quick Notes Right in Your Browser
fun

Online Notepad: Quick Notes Right in Your Browser

Take quick notes without any app installation. Your browser becomes a lightweight, distraction-free notepad with auto-save.

Lottery Number Generator: Get Random Picks Instantly
fun

Lottery Number Generator: Get Random Picks Instantly

Generate random lottery numbers for Mega-Sena, Powerball, EuroMillions, and more. Learn how lottery probability works.

CSR Decoder: Understanding SSL Certificate Signing Requests
crypto

CSR Decoder: Understanding SSL Certificate Signing Requests

Decode and verify CSR (Certificate Signing Request) files. Learn what's inside a CSR and how SSL certificate issuance works.

Dice Roller: Generate Random Numbers for Tabletop Games
fun

Dice Roller: Generate Random Numbers for Tabletop Games

Roll virtual dice for D&D, board games, and more. Learn about dice notation, probability, and how random number generation works.

Random Number Generator: Ranges, Distributions, and Use Cases
generators

Random Number Generator: Ranges, Distributions, and Use Cases

Generate random numbers with custom ranges and learn about true vs pseudo randomness, distributions, and cryptographic security.

Internet Speed Test: How to Check Your Connection Speed
network

Internet Speed Test: How to Check Your Connection Speed

Test your internet speed and understand what download, upload, and ping numbers actually mean for your daily use.

Keyboard Shortcuts Every Developer Should Know
dev-reference

Keyboard Shortcuts Every Developer Should Know

Master keyboard shortcuts for VS Code, browser DevTools, terminal, and OS. Boost your development speed dramatically.