Guides

Color Models Explained: HEX, RGB, HSL, and When to Use Each

Three ways to describe the same color, each suited to a different task. HEX for code, RGB for compositing, HSL for design decisions.

Cron Expressions Explained: Scheduling Jobs the Right Way

The five fields of a cron expression, the shortcuts everyone forgets, and the timezone mistakes that cause 3 AM pages.

HMAC vs Hash: Why Signing Matters for APIs

A plain hash proves a message has not changed by accident. HMAC proves it has not changed on purpose. Here's why API signing uses one and not the other.

JSON vs YAML: Which Config Format to Use

JSON and YAML solve the same problem in two very different ways. Here's how to pick between them based on the audience for your config file.

JWT Tokens Explained: Structure, Security, and Common Mistakes

How JSON Web Tokens are built, what the header and payload really contain, and the security mistakes that bite production apps.

Markdown Cheat Sheet: Everything You Need in One Page

Every Markdown element you'll actually use, with copy-paste examples — headings, lists, links, tables, code blocks, and the GitHub-flavoured extensions.

Regex Cheat Sheet for Developers

The regex patterns you actually use in real code — anchors, character classes, quantifiers, groups, and the gotchas that cost an afternoon.

SHA-256 vs MD5: When to Use Which Hash Algorithm

MD5 is fast but broken. SHA-256 is the safe default. Here's when each shows up in production, and why checksum use cases are the only reason MD5 still exists.

URL Encoding Explained: Percent-Encoding, When You Need It, and Common Bugs

Why spaces become %20, when to encode path segments vs query parameters, and why double-encoding is the most common URL bug.

UUID vs ULID vs NanoID: Picking the Right ID for Your App

Four ID formats compared — what each looks like, how they sort, how much entropy they carry, and which fits which use case.

How to Create a Strong Password

Learn what makes a password truly secure, common mistakes to avoid, and how to manage dozens of strong passwords without memorizing them.

Base64 Encoding Explained

What Base64 is, how it works, when to use it, and common pitfalls — with practical examples you can test right away.