Practical guides for the web technologies you work with every day. JSON, JWTs, Base64, regex, hashing — explained with real examples, not just definitions. Every article pairs with a free Devryo tool so you can test ideas directly in your browser.
Everything about ISO 8601 — the YYYY-MM-DDTHH:mm:ssZ format, timezone offsets (Z vs +00:00), durations, week numbers, and how to use it in JavaScript, Python, PHP, SQL, and HTML.
Everything you need to know about Cron expressions — the five-field syntax, special characters, common schedule patterns, timezone gotchas, and how Cron works in GitHub Actions, AWS EventBridge, Laravel, and Kubernetes.
How to convert JSON to TypeScript interfaces automatically — the type mapping rules, how to handle null values, common patterns for API response wrappers, and when to use Zod for runtime validation instead of plain interfaces.
A developer's guide to UUID — how v4 random generation works, when to use v1 vs v5 vs v7, the difference between UUID and GUID, and best practices for storing UUIDs as database primary keys.
A practical guide to CSV files. Learn the format, how to handle commas inside values, why Excel mangles UTF-8 on Mac, and when converting to JSON makes sense — with code examples in JS and Python.
A beginner's guide to Markdown — the lightweight syntax behind GitHub READMEs, Notion, and dev.to. Includes a full cheat sheet, rendered HTML examples, and notes on GitHub Flavored Markdown differences.
Timezone bugs are subtle and painful. Learn the difference between UTC offsets and named zones, why you should always store UTC in your database, and how to handle DST correctly in JavaScript and Python.
A beginner's guide to YAML. Covers indentation rules, data types, multi-line strings, and comments — with side-by-side JSON comparisons. Explains why YAML is used in Docker Compose, GitHub Actions, and Kubernetes configs.
Learn SQL formatting conventions with before/after examples. Covers keyword capitalization, one-clause-per-line rules, subquery indentation, and leading vs trailing commas — plus how to auto-format in one click.
Understand how text diff tools work. Covers unified diff format, line-level vs character-level comparison, how Git uses diff, and practical uses in code review, config management, and document editing.
Start with JSON and Base64 — they show up everywhere in APIs and auth flows. Both guides include interactive Devryo tools so you can try examples immediately.