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Clear, practical explanations of the things developers actually look up — JSON, regex, JWTs, cron, hashing, encoding and more. Every guide pairs with a free tool you can run right in your browser.
A practical guide to Base64: how binary-to-text encoding works, the 33% size cost, data URLs, JWTs, and the cases where you should never reach for it.
MD5 and SHA-1 are broken for security but fine as checksums. Here's when to use SHA-256/512 and why passwords need bcrypt or argon2 instead.
A practical guide to writing clean Markdown for READMEs and docs: headings, code fences, tables, task lists, links, badges, and structure that actually helps.
An honest engineer's guide to coding on Android: editors, on-device compilers, offline workflows, real limitations, and where a phone actually fits.
A practical guide to HEX, RGB, and HSL color formats in CSS — how each works, how alpha fits in, when HSL is easier, and how to convert between them.
A practical guide to cron expressions: the five fields, special characters, common schedules, timezone gotchas, and how to verify your next runs.
A practical guide to CSV for developers: delimiters, quoting rules, embedded commas and newlines, encodings, Excel quirks, and clean conversion to JSON.
Encoding, hashing, and encryption look similar but solve different problems. A developer's guide to telling them apart and avoiding the classic security mistakes.
A practical, no-hype guide to how JWTs work: anatomy, base64url, claims, signing vs encryption, verification, expiry, and the security mistakes to avoid.
A practical guide to HTML escaping: when to encode <, >, &, and quotes, named vs numeric entities, context-aware escaping, and how it stops XSS.
A practical comparison of JSON, YAML, and TOML for configuration files: readability, comments, data types, tooling, and the failure modes that bite developers.
A practical guide to camelCase, snake_case, kebab-case, PascalCase and SCREAMING_SNAKE_CASE: where each belongs, why it matters, and how to convert between them.
Merge, split, and rotate PDFs entirely in your browser — no uploads, no accounts. How client-side PDF editing works and a practical step-by-step guide.
Learn regex from the ground up in JavaScript: literals, character classes, quantifiers, anchors, groups, alternation, and flags, with real working patterns.
Ten practical, correct-ish regex patterns for emails, URLs, hex colors, ISO dates, slugs, and whitespace cleanup, with honest caveats about where regex breaks.
A practical guide to managing servers from your phone with SSH: key vs password auth, SFTP transfers, essential commands, and quick on-call fixes.
A developer's guide to strong passwords: entropy math, why length beats complexity, passphrases, managers, and how a CSPRNG-backed generator works.
A practical guide to JSON syntax, the parse errors that bite developers most often, how to read parser messages, and how to fix each one fast.
A practical guide to Unix epoch time, seconds vs milliseconds, UTC vs local, the 2038 problem, ISO 8601, and converting timestamps safely in code.
A practical guide to percent-encoding: reserved vs unreserved characters, encodeURI vs encodeURIComponent, encoding query params, and the space/plus bug.
A practical guide to choosing between UUIDs and auto-increment integer primary keys: sharding, index performance, count leakage, and which UUID version to use.
A practical guide to parsing and validating JSON in JavaScript: JSON.parse pitfalls, try/catch, reviver functions, schema validation, and untrusted input.
How in-browser tools differ from server-upload tools, what "data never leaves your device" actually means, and how to verify the claim yourself.
A balanced, practical look at XML and JSON: their history, structure, schemas, namespaces, and the real situations where each one is still the right call.