Guides & tutorials
Developer guides
Short, practical walkthroughs with copy-paste examples. Each guide pairs with a browser-based tool so you can try the workflow immediately.
JSON Formatting: A Practical Guide
Format and validate JSON, fix 'unexpected token' errors, and choose between minified and pretty-printed output.
Regex Testing: Flags, Groups, and Debugging
How flags change matching, how capture groups extract data, and how to fix patterns that match too much.
Converting cURL to fetch and axios
Turn cURL examples from API docs into working JavaScript — and know what needs manual review before shipping.
Decoding and Understanding JWTs
What a JSON Web Token contains, the difference between decoding and verifying, and the security rules that matter.
Base64 Encoding, Explained
Why Base64 exists, how it differs from encryption and Base64URL, and when to use data URIs.
HEX, RGB, and HSL Color Formats
How the three web color formats relate, when to use each, and why HSL makes building palettes easier.
JSON vs YAML: When to Use Each
Syntax differences, the type-inference gotchas that bite people, and a safe way to convert between them.
Optimizing SVGs for the Web
Why exported SVGs are bloated, what optimization safely removes, and when to inline vs. link them.
The Bit-Level Mechanics of Base64 Encoding
How 3 bytes become 4 characters, worked bit-by-bit, plus padding, alphabets, and why it isn't encryption.
How JSON Parsers Work
Tokenizing, recursive-descent parsing, and exactly why trailing commas and single quotes fail.
Regex Engines Explained
Backtracking NFAs, catastrophic backtracking, ReDoS, and why linear-time engines can't do backreferences.
JWT Security Deep Dive
The alg:none bypass, RS256/HS256 algorithm confusion, and the claims a valid signature doesn't check.
Color Theory for Developers
Gamma correction, why averaging hex colors gives the wrong gray, and why HSL isn't perceptually uniform.
The Anatomy of an HTTP Request
The raw wire format, what cURL flags actually send, and why CORS preflight only happens in browsers.
How SVG Rendering Works
The path-data mini-language, why exported SVGs bloat, and what an optimizer's passes actually remove.
YAML's Hidden Traps
The Norway problem, octal permission ambiguity, and why quoting is the only real fix.
Character Encoding Explained
ASCII, code pages, the codepoint-vs-encoding distinction, and how UTF-8 actually packs bits.
URL Encoding and Percent-Encoding
What RFC 3986 actually escapes, why + means space in query strings, and how double-encoding happens.