How to Write a Robots.txt File That Doesn’t Block Your Whole Site
Learn how to write a robots.txt file safely, with a worked example that blocks only /admin/, plus testing steps and the mistakes that can block your whole site.
What Is an XML Sitemap and Does Your Site Need One
An XML sitemap is a list of URLs that helps search engines discover your pages. Learn what it contains, how to submit it, and why it does not guarantee indexing.
How to Convert Time Zones Without Missing Your Meeting
Learn a reliable way to convert time zones: start from UTC, check daylight saving time, and confirm every local time before you send the invite.
How to Read a JWT Payload Without Trusting It
Learn how to decode a JWT payload by splitting the token and Base64 decoding it — and why decoding is never the same as verifying.
What Is HTML Minification and Should You Use It
Learn what HTML minification does, what it removes, and when it is worth using — plus why you should always keep an unminified source.
How to Format CSS So You Can Actually Read It
Learn how to format CSS with consistent indentation, one declaration per line, and clear grouping so your stylesheets stay easy to read, review, and maintain.
How to Crop an Image Without Cutting Off What Matters
Crop without losing the subject: rule of thirds, eyes in frame, and a 4000×3000 to 1080×1080 square worked example.
What Is SHA-512 and When Do You Need It
What SHA-512 is, how its 128-character hash works, when to use it for checksums, and why passwords need bcrypt or Argon2.
How to Tell If a Number Is Prime (Without Trying Every Divisor)
Learn the square-root shortcut for primality testing, with 97 worked out step by step by checking only 2, 3, 5, and 7.
How to Read and Write Roman Numerals Without Guessing
Learn the seven Roman numeral symbols, the six subtractive pairs, and a step-by-step method, with 2024 worked out as MMXXIV.