Free Online Tools & Practical Guides
Browser-based tools paired with in-depth guides — built for developers, learners, and the curious. No sign-up, no tracking.
Featured Blog Guides
Practical deep dives to help you use tools better, faster, and smarter
Privacy Online Isn't About Hiding: Why It Matters for Everyone
Privacy isn't a feature for people with something to hide. Here's what actually leaks when you load a webpage — and the layered tech that protects it.
Git Worktree for Parallel Development
git worktree has been around since 2015, but coding agents made it relevant again. A practical guide to running multiple branches in one repo.
Database Indexes Explained: B-Tree, B+Tree, Clustered, LSM
B-Tree and B+Tree differ by one detail — leaf-node linkage — and that decides range-query performance. A practical reference.
Why Your Container Ignores SIGTERM: PID 1 and npm start
A Kubernetes pod waits the full grace period and gets SIGKILL'd. The real culprit is rarely the application — it's PID 1.
JWT Storage: localStorage, Cookies, and the XSS Problem
Where to actually store JWT tokens — localStorage, sessionStorage, httpOnly cookies, or memory. The XSS vs CSRF tradeoffs that decide it.
YAML Parsing Traps: The Norway Problem and 6 Other Bugs
YAML's implicit typing causes real production bugs. The Norway problem, octal version strings, and 5 other traps every config writer should know.
How DNS Actually Works: Address Bar to Server
Trace a DNS lookup step by step with real dig output, resolver caching behavior, and what happens when DNS goes wrong.
Regex for Humans: A No-Fear Practical Guide
Start with 10 regex patterns you can use in 5 minutes. Progress to real log parsing, data cleaning, and validation with pitfalls to avoid.
The Monty Hall Problem: When Intuition Fails
Why switching doors wins 2/3 of the time, backed by simulation data, Bayesian reasoning, and the real story behind the controversy.
Utility Tools
Practical tools for everyday calculations and conversions
Unit Converter
Convert length, weight, and temperature units instantly
Text Counter
Count characters, words, sentences, and paragraphs
QR Code Generator
Create QR codes from URLs or text
Color Converter
Convert between HEX, RGB, and HSL colors
D-Day Calculator
Calculate days until or since any date
BMI Calculator
Calculate your Body Mass Index
JWT Debugger
Decode and inspect JSON Web Tokens
JSON/YAML Converter
Convert and prettify JSON and YAML
Kubeconfig Manager
Manage Kubernetes kubeconfig files easily
Text Share
Compress text and share as a URL with optional encryption
Image Tools
Convert, compress, resize, crop and edit images in your browser
Image Format Converter
Convert between PNG, JPEG, and WebP
Image Compressor
Reduce image file size with quality control
Image Resizer
Resize images to exact dimensions
Image Cropper
Crop images with precision selection
Image Editor
Adjust brightness, contrast, and filters
Image Merger
Combine up to 10 images — grids, free layout, size-fit options
Fun & Random
Random generators and decision makers for fun
Spin the Wheel
Random selection wheel with custom options
Ladder Game
Korean-style random selection game
Rock Paper Scissors
Classic game against the computer
Team Generator
Divide people into random teams
Lotto Generator
Generate random lottery numbers
Slot Machine
Spin the emoji slots for fun
Card Draw
Draw random cards from a deck
Drawing Lots
Pick a lot to test your luck
Random Number
Generate random numbers in any range
Coin Flip
Flip a virtual coin - Heads or Tails
Dice Roller
Roll virtual dice with animations
Yes or No
Let fate decide for you
Personality Quizzes
Discover more about yourself with fun quizzes