MD5 vs SHA-256: Which Hash Should You Use
MD5 vs SHA-256: MD5 is a 32-char hash broken for security, SHA-256 is a 64-char hash. Learn checksums and why passwords need bcrypt or Argon2.
How to Use a Stopwatch to Actually Get Things Done
Learn how to use a stopwatch to get things done: Pomodoro 25/5 sessions, time-boxing, honest measurement, and breaks that restore focus.
How to Split a PDF Into Smaller Files
Learn how to split a PDF into smaller files by page range. Keep your original safe, check the page count, and share only the pages people need.
How to Check Color Contrast Before You Publish (WCAG Basics)
Check color contrast before you publish. Learn the WCAG ratios: 21:1 black on white, 4.5:1 for normal text, 3:1 for large text, with a worked grey-on-white example.
What Is a JWT and Why You Should Never Put Secrets in One
A JWT payload is readable Base64, not encrypted. Learn the header.payload.signature format, what sub, iat, and exp mean, and why secrets never belong in a token.
How to Convert Units Without Getting the Wrong Answer
Convert units safely: write the unit, check multiply vs divide, and remember temperature needs an offset. Worked examples for km, kg, and Celsius.
How to Format JSON So You Can Actually Read It
Learn how to format JSON with consistent indentation, no trailing commas, and matched brackets, plus a worked example and a validation checklist.
What Is Base64 Encoding (and Why It Makes Files Bigger)
What is Base64 encoding? Learn the 64-character alphabet, why it makes files about 33% bigger, and why it is not encryption.
How to Compress a PDF Without Ruining It
Learn how to compress a PDF without ruining it, with image tips, font checks, and a worked 5 MB example.
How to Merge Multiple PDFs Into One File (and When Not To)
Learn how to merge multiple PDFs into one file in the right order, verify page counts, handle scanned pages, and know when to keep files separate.