Blog
Technical articles, tutorials and guides about JSON, TypeScript, Base64, JWT, and the tools you use every day.
DevOps & APIs
· 7Five fields or six? Cron syntax across GitHub Actions, Kubernetes, AWS and Quartz
The same cron line means different things on four of the schedulers people use most. The fields agree; the day numbering, the time zone and the overlap policy do not.
The crontab file: PATH, MAILTO and the `%` that becomes a newline
A crontab is not a shell script. It runs with a different PATH, mails its output to somewhere you are not looking, and turns an unescaped % into a newline.
What Is a Cron Expression? The Five Fields, Explained
A cron expression is five fields that describe a time. What each field matches, why */7 gives you nine runs an hour, and when the first of the month fires on a Monday too.
SQL Formatting: The 10-Second Habit That Saves Hours
SQL formatting takes ten seconds per query and saves hours of debugging. Here's what it catches, why your IDE's formatter isn't enough, and how to make it a habit.
Cron Expressions: Writing Schedules That Actually Run When You Expect
Stop guessing why your cron jobs run at 3 AM instead of 3 PM. Learn how cron evaluates time, handles timezones, and why concurrency breaks silently.
Timestamp Conversion: Why UTC Isn't Optional
A Unix timestamp is just a number. Whether that number means what you think depends on three things the docs assume you already know.
HTTP Status Codes You Should Actually Know
Most developers know 200, 404, and 500. The real debugging starts with the other codes that nobody memorizes.
Security
· 4MD5 vs SHA1 vs SHA256: What Actually Matters
MD5, SHA1, and SHA256 all serve different purposes. Here's a practical framework for choosing between them without cargo-culting security advice.
What Developers Get Wrong About Base64 Encoding
Learn the three Base64 pitfalls that cause real production bugs: confusing encoding with encryption, assuming padding rules are universal across languages, and ignoring the 33% size overhead.
Password Generators: What Makes a Password Actually Secure
Length beats complexity every time. Here's what password generators get right and wrong, and how to create passwords that are both secure and usable.
How to Decode a JWT Token (And Actually Understand What's Inside)
JWTs aren't encrypted. You can decode them without a secret key. Here's how to read the header, payload, and signature, and what to look for when debugging auth issues.
JSON & Data
· 3JSON to TypeScript: The Edge Cases Automation Misses
Converting JSON to TypeScript interfaces is straightforward until you hit nullable fields, deeply nested objects, or arrays of unions. Here's how to handle the cases that automated tools get wrong.
Why Your JSON Validator Keeps Failing (and It's Probably Not the JSON)
Learn the four hidden reasons your JSON validator rejects valid-looking data: invisible characters sneaking in from terminals, trailing commas that JavaScript allows but JSON doesn't, and values like NaN that serialize into nothing.
JSON vs YAML: The Config File Debate
Your CI pipeline just failed because a config value silently changed type. Here's how JSON and YAML behave in the real world and when each one makes sense.
Web Platform
· 2HTML Encoding: Characters and Charset Issues That Break Your Pages
Three causes of HTML encoding bugs, from unescaped angle brackets to charset mismatches, and a systematic way to fix them.
URL Encoding: What That %20 Actually Means
One wrong function call is all it takes to break a URL. Here's how percent-encoding really works and which specific mistakes to avoid.
Developer Tools
· 2What UUIDs Actually Guarantee (and What They Don't)
UUID collisions are astronomically unlikely until they happen. Here's when you can rely on them, which version to use, and what they don't protect against.
Regex for the Real World: Three Patterns That Solve Most Problems
Three regex patterns handle 90% of real-world text tasks. Here's how to use each one correctly and the edge cases that break them.