Developer Tools

Twitter, Discord, and Instagram all built custom ID systems because UUID couldn't handle time-sortability, distributed generation, and 64-bit constraints simultaneously. Here's how Snowflake IDs work, what ULID and CUID2 offer, and when each alternative makes sense.

REST URL conventions, API versioning strategies (URL path vs header vs date-based like Stripe), trailing slash canonicalization, URL length limits, and the link rot problem — URL design decisions made at launch determine API maintainability for years.

Learn what bcrypt is, how the cost factor and salt work, how bcrypt hashes are structured, and how to use a free bcrypt generator to test and verify password hashes in your development workflow.

Most passwords that "pass" complexity rules are still cracked in minutes. Here's how attackers actually work, what password entropy means, and why random generation beats human-chosen passwords every time.

"What's different between these two JSON documents" and "what's the smallest sequence of operations that transforms one into the other" are related but distinct questions — the second is what JSON Patch (RFC 6902) standardizes. Here's the six JSON Patch operations, the JSON Pointer path syntax they rely on, how the test operation enables optimistic concurrency control, and when the simpler JSON Merge Patch is sufficient instead.

Roughly 1 in 12 men have some form of red-green color vision deficiency — meaning "red means error, green means success" relies on a color distinction that's specifically the hardest for the most common type of color blindness. Here's how different CVD types affect color perception differently, why redundant non-color signals (icons, labels, patterns) are the core fix, and how CVD simulation reveals confusable color pairs during design review.

Learn how cron expression syntax works, what each field means, common schedules explained in plain English, cron pitfalls like timezone issues and overlapping jobs, and how to use a free cron explainer tool.

JSON has no comments, no date type, and a number precision problem that caused Twitter to change their API. Here's how JSON compares to XML, YAML, MessagePack, and Protocol Buffers, when each format makes sense, and what JSON Schema adds.

Learn how to write and debug regular expressions using a live tester — with syntax reference, real examples for email validation, log parsing, and URL extraction, and tips on greedy vs. lazy matching.

SHA-1 and MD5 are fast by design — which is why GPUs crack them in hours after a breach. bcrypt's deliberate slowness and automatic salting are its defence. Here's how bcrypt works, the 72-byte limit, choosing a cost factor, and when Argon2 is the better choice.