Dev Productivity Tools

What this pillar is really about

These are the little-utilities-that-you-use-daily. Not because they're exciting, but because every working engineer needs them 10 times a week and the existing options bury the tool under ads, send your data to a server, or just aren't quite right.

None of these is novel — regex testers and cron builders have existed for decades. What makes these worth using: they're fast, correct, and stay out of your way. You land on the page, the tool works, you leave.

Everyday workflows that chain these tools

• Debugging a log file: paste a sample line into Regex Tester → extract the timestamp → paste it into Timestamp Converter → confirm it's in the right timezone.
• Scheduling a job: build the schedule in Cron Builder → copy the expression → paste into your crontab or CI config.
• Debugging an API response: get a weird status code → check the HTTP Status Codes reference → realize the difference between 401 and 403.
• Design-dev handoff: designer sends a hex → check Color Picker's WCAG contrast against your background → red-flag if below AA.

Design principles across the pillar

• No sign-up, no ads over UI. Every tool works the instant you land.
• Explain, don't just compute. Cron builder shows the human-readable explanation AND the next 5 runs. HTTP codes page shows why 422 isn't 400.
• Live by default. Type and see. No "Run" button unless there's a reason (Hash Generator auto-runs, Regex Tester auto-runs).
• Standards-accurate. WCAG 2.1 contrast uses the real linear-sRGB luminance formula. Cron uses POSIX OR semantics for DOM/DOW, matching cron behavior.

All 12 tools in this pillar

• Color Picker — Pick colors, convert hex/RGB/HSL/OKLCH, and check WCAG contrast.
• Regex Tester — Test regular expressions with live match highlighting and explanation.
• Timestamp Converter — Convert Unix timestamps, epoch seconds/milliseconds, and ISO 8601 dates.
• Cron Builder — Build and parse cron expressions with human-readable explanations.
• HTTP Status Codes — Full HTTP status code reference with explanations and when to use each.
• Word Counter — Count words, characters, sentences, paragraphs, and lines. Reading time estimate, char-limit indicators for X, LinkedIn, meta titles, and more.
• Lorem Ipsum Generator — Generate placeholder text — words, sentences, or paragraphs. Classic lorem ipsum plus alternatives (hipster, cupcake, pirate). HTML-wrapped output option.
• Subnet / CIDR Calculator — Calculate IPv4 subnets — network, broadcast, usable range, wildcard mask. Input CIDR (/24) or dotted mask (255.255.255.0). Binary visualization.
• Aspect Ratio Calculator — Calculate aspect ratios (16:9, 4:3, 21:9, etc.). Given W:H and one dimension, get the other. Responsive padding-top % for CSS aspect-ratio containers.
• Case Converter — Convert text between camelCase, PascalCase, snake_case, kebab-case, SCREAMING_CASE, Title Case, sentence case, and more. Bulk mode.
• Email & URL Extractor — Extract every email address and URL from a block of text. Regex-based, case-insensitive, deduplicated, sorted output.
• User Agent Parser — Parse any User-Agent string into browser, OS, device, and engine. Or detect your own. Built on the maintained ua-parser-js dataset.

Further reading

• The Only Regex Cheatsheet You Need in 2026
• Catastrophic Backtracking: The Regex That Kills Your Server
• Cron Expression Syntax, Explained by Field
• Cron Pitfalls: Timezones, DST, and Missed Runs
• Unix Timestamps and Timezones: What Can Go Wrong
• When to Use 422 vs 400 (and Other Status Debates)
• WCAG Contrast Explained

Other pillars

• Data & Format — JSON, YAML, XML, CSV, SQL, Markdown.
• Encoding & Crypto — Base64, URL, JWT, hashes, UUID, QR, password.
• Frontend & Design — Flexbox, Grid, box shadow, favicon.

Curated and maintained by Mian Ali Khalid. Last updated 2026-04-25.