•9 min read
Mock Data for Testing: Faker, Seeded Randomness, and Locales
Generate fake test data that doesn't break tests: seeded randomness, locale-aware Faker, realistic vs predictable tradeoffs, and MSW/Playwright integration patterns.
Blog
Articles, tutorials, and updates about developer tools and productivity.
•8 min read
Image Boxing: Letterbox, Pillarbox, and Social Media Aspect Ratios
Letterbox, pillarbox, and windowbox explained: CSS object-fit values, sharp server-side boxing, canvas padding, and social media aspect ratios (1:1, 4:5, 9:16, 16:9).
•7 min read
OPML and RSS: Importing, Exporting, and Migrating Feed Subscriptions
OPML file format for RSS reader interop: structure, extraction with XPath/DOMParser, Feedly/Inoreader/NetNewsWire compatibility, and programmatic feed URL discovery.
•8 min read
Comparing Word Documents: docx Internals and Diff Workflows
Compare .docx files reliably: docx is a ZIP of XML, byte vs structural vs semantic comparison, Word's built-in Compare limitations, and pandoc-to-markdown diff workflows.
•9 min read
Roman Numerals Guide: Rules, Subtractive Notation, and Conversion
Roman numerals explained: I/V/X/L/C/D/M symbols, additive and subtractive rules, the 3999 ceiling, MCMLXXXIV decoded, and working JS/Python converters.
•10 min read
Password Strength Explained: Entropy, zxcvbn, and Crack Times
Why "Password1!" is weak: entropy math, hardware crack rates, zxcvbn scoring, NIST 2024 guidance against forced complexity, and Have I Been Pwned breach checking.
•11 min read
HTTP Status Codes Guide: 1xx–5xx, Retry-Safe, and REST Conventions
HTTP status codes for REST APIs: all five classes, 422 vs 400 validation, 401 vs 403, retry-safe codes (408, 429, 503), and common anti-patterns to avoid.
•10 min read
MIME Types Guide: Content-Type, Charsets, and nosniff
Set Content-Type correctly: MIME anatomy, top-level types, charset parameters, vendor types (application/vnd.*), MIME sniffing risks, and X-Content-Type-Options: nosniff.
•11 min read
Mermaid Diagrams Guide: Flowcharts, Sequence Diagrams, and Docs-as-Code
Mermaid syntax for every diagram type: flowcharts, sequence diagrams, class diagrams, ER diagrams, rendering on GitHub/GitLab/Notion, and mmdc CLI for docs-as-code.
•10 min read
Meta Tags and Open Graph: SEO, Social Previews, and OG Images
Write meta tags that actually work: Open Graph for Facebook/LinkedIn, Twitter Cards, og:image (1200×630), JSON-LD structured data, and dynamic OG images with @vercel/og.
•10 min read
Python Formatter Guide: Black, ruff format, and PEP 8
Format Python code consistently: Black vs ruff format vs autopep8, line length debates, pyproject.toml config, pre-commit integration, and CI enforcement.
•10 min read
Color Palette Workflows: Extraction, Harmony, and Design Systems
Build color palettes that work: harmony rules, k-means extraction from images, design system scales in OKLCH, tints and shades, and WCAG contrast checks.
•9 min read
Docker Run to Compose: Converting Commands to compose.yaml
Convert docker run commands to compose: flag-to-field mapping (-p, -v, -e, --restart), bind mounts vs named volumes, override files, and Compose v2 vs v1.
•8 min read
SCSS Formatter Guide: Prettier, stylelint, and Nesting Rules
Format SCSS consistently: Prettier config, stylelint stylistic vs logic rules, nesting depth limits, @use/@forward replacing @import, and pre-commit integration.
•8 min read
JavaScript Keycode Reference: event.key vs event.code in 2026
Handle keyboard events correctly: event.key vs event.code, deprecated keyCode, cross-platform modifiers (Cmd/Ctrl), shortcut libraries, and international keyboard pitfalls.
•8 min read
Phone Number Parsing Guide: E.164, libphonenumber, and International Formats
Parse phone numbers correctly: E.164 format, why regex validation fails internationally, libphonenumber usage, display vs storage formats, and extension handling.
•8 min read
URL Slugify Guide: Unicode, Transliteration, and Collision Handling
Generate SEO-friendly URL slugs: Unicode NFD normalization, transliteration beyond Latin, stop-word tradeoffs, collision handling, and slug-vs-ID URL patterns.
•8 min read
Base32 Encoding Guide: RFC 4648, Crockford, and TOTP Secrets
Base32 encoding explained: RFC 4648 alphabet, Crockford variant (excludes I/L/O/U), z-base-32, why TOTP uses Base32, padding rules, and size overhead vs Base64.
•7 min read
ASCII Art Generator Guide: Figlet, CLI Banners, and Box Drawing
Generate ASCII art for CLIs and READMEs: Figlet fonts, width constraints, Unicode box-drawing characters, and programmatic generation with figlet/pyfiglet.
•8 min read
MAC Address Guide: OUI, Locally-Administered Bit, and Privacy Randomization
MAC address structure: OUI + NIC split, I/G and U/L bits, well-known prefixes (Docker, VMware), privacy randomization in modern OSes, and generating valid random MACs.