Category: Developer Guides

URL encoding and HTML encoding look similar but do different jobs. Confusing them causes security bugs, broken links and garbled text. Here is when to use each. Read more →

Hashing turns any input into a fixed-length fingerprint — and the algorithm choice matters enormously. Here is what MD5, SHA-256 and bcrypt actually do and when to use each. Read more →

File permission numbers like 755 and 644 are simpler than they look. Here is the quick mental model: three groups, and read/write/execute worth 4, 2 and 1. Read more →

JSON parsing errors are almost always one of a small set of fixable mistakes. Here are the eight most common ones and how to spot them fast. Read more →

Regular expressions are one of the most avoided tools in programming — and one of the most useful once you learn eight or nine patterns. This guide gets you reading and writing real regex. Read more →

Timezone bugs are behind a huge share of date and time problems in software. This guide explains Unix timestamps, why UTC matters, and the rules that make datetime code reliable. Read more →

UUIDs look random but they come in versions with very different properties. Here is what v1, v4 and v5 actually generate and which one belongs in your database or API. Read more →

CIDR notation shows up in every cloud config, firewall rule and Docker network. Here is what the slash number means and how to read any subnet at a glance. Read more →