Security & Privacy
How to Verify a SHA-256 Checksum on Windows, Mac and Linux
The exact commands to check a download's SHA-256 checksum on Windows, macOS and Linux, how to compare it without eyeballing 64 characters, and what a match proves.
Blog
Guides, tips and how-tos for getting more out of free web tools, from formatting JSON to building better passwords.
Web & SEO
QR Code Not Scanning? Causes and Fixes Before You Print
A QR code that works on screen can fail on paper. Here's how data length, margins, colors, logos and print quality break scanning, and how to test first.
Developer Guides
"Unexpected Token" in JSON: What It Means and How to Fix It
The token in the error message is the clue. Here's what "Unexpected token" means for each common character, from an HTML error page to a hidden BOM, and how to fix it.
Everyday Math & Text
How to Figure Discounts, Sales Tax and Tips in Your Head
One trick covers most shopping math: find 10% first. Here's how to price discounts, add sales tax and pick a tip in your head, and why stacked discounts mislead.
Web & SEO
Why Google Rewrites Your Title Tags and Meta Descriptions
Google can replace your title tag and meta description with text from the page. Here's what its documentation says causes it and how to write ones it keeps.
Developer Guides
What Is a JWT? How to Read One Without Trusting It
A JWT isn't encrypted: anyone can decode it. We take one token apart by hand, explain its claims and signature, and cover the checks a server must make.
Security & Privacy
Passkeys vs Passwords: How Passkeys Work
A passkey replaces the secret you type with a key pair: the site keeps a public key, your device signs a one-time challenge. Here's why that stops phishing.
Everyday Math & Text
APR vs Interest Rate: What's the Difference?
The interest rate sets your monthly payment. The APR folds points and lender fees into one yearly rate. Here's how it's calculated and when it misleads.
Developer Guides
camelCase vs snake_case vs kebab-case: Naming Conventions
camelCase, snake_case, PascalCase and kebab-case each have a home. Here's which style each language and format expects, and how to convert at the boundaries.
Everyday Math & Text
How to Count Days Between Dates (Inclusive or Not)
Monday to Friday is 4 days or 5, depending on how you count. Here's when to include the end date, how to count business days, and how legal deadlines are counted.
Everyday Math & Text
SMS Character Limits: Why 160 Becomes 70
A single emoji or curly apostrophe can cut an SMS limit from 160 characters to 70 and double the cost. Here's how SMS encoding and segments work, with real examples.
Web & SEO
What Favicon Sizes Do You Need?
You don't need twenty icon files. Here's the small favicon set that covers tabs, Google results, iPhones and installed web apps, and the exact HTML to add.