Toolery

Toolery Blog

Tips, guides, and insights about online tools, productivity, and fun discoveries

Posts are grouped into Dev (regex, config formats, HTTP, DNS, datetime), DevOps (Kubernetes, containers, SSH, cron, homelab), Database (indexes, isolation levels), Security (JWT, password entropy, phishing), Productivity (dotfiles, time blocking, Obsidian + Claude Code), plus Image and Fun.

Each post clears one specific confusion rather than summarizing the topic. The deeper pieces: the YAML Norway problem, Postgres isolation levels, why containers ignore SIGTERM, and where to store JWTs. Filter by category or tag below.

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Security April 28, 2026

Privacy Online Isn't About Hiding: Why It Matters for Everyone

Privacy isn't a feature for people with something to hide. Here's what actually leaks when you load a webpage — and the layered tech that protects it.

#privacy #security #web #tracking
10 min read
Productivity April 27, 2026

Git Worktree for Parallel Development

git worktree has been around since 2015, but coding agents made it relevant again. A practical guide to running multiple branches in one repo.

#git #ai-workflow #productivity
11 min read
Database April 25, 2026

Database Indexes Explained: B-Tree, B+Tree, Clustered, LSM

B-Tree and B+Tree differ by one detail — leaf-node linkage — and that decides range-query performance. A practical reference.

#database #indexing #performance #sql +1
12 min read
DevOps April 23, 2026

Why Your Container Ignores SIGTERM: PID 1 and npm start

A Kubernetes pod waits the full grace period and gets SIGKILL'd. The real culprit is rarely the application — it's PID 1.

#containers #kubernetes #docker #debugging +1
12 min read
Security April 22, 2026

JWT Storage: localStorage, Cookies, and the XSS Problem

Where to actually store JWT tokens — localStorage, sessionStorage, httpOnly cookies, or memory. The XSS vs CSRF tradeoffs that decide it.

#jwt #authentication #security #web
9 min read
Dev April 21, 2026

YAML Parsing Traps: The Norway Problem and 6 Other Bugs

YAML's implicit typing causes real production bugs. The Norway problem, octal version strings, and 5 other traps every config writer should know.

#yaml #config-format #debugging #reference
8 min read
Database April 21, 2026

Transaction Isolation Levels in Postgres and MySQL

The SQL standard names four isolation levels. Postgres and MySQL implement them differently — and Postgres' REPEATABLE READ is not the standard's.

#database #postgres #mysql #sql +1
13 min read
Dev April 20, 2026

Why QR Codes Fail to Scan: A Debugging Checklist

Seven concrete reasons QR codes fail to scan — module size, quiet zone, error correction, contrast, URL length, and the surface they're printed on.

#qr-code #debugging #reference
8 min read
DevOps April 18, 2026

SSH Config Tricks: Aliases, Jump Hosts, and ControlMaster

Real SSH config patterns that save 10+ minutes a day — host aliases, ProxyJump, ControlMaster multiplexing, Include directives, and per-host keys.

#ssh #devops #cli #productivity
10 min read
Dev April 17, 2026

Timezone Bugs in Production: DST, Leap Seconds, and tzdata

Real timezone bugs that shipped — the DST repeating hour, the 2012 leap second crash, tzdata release lag, and why 'just use UTC' doesn't fully save you.

#timezone #datetime #production #debugging
11 min read
Productivity April 5, 2026

Time Blocking for Developers: Protecting Deep Work in a Fragmented Day

How to apply time blocking as a developer — context switching costs, scheduling deep vs. shallow work, and why most calendar systems fail programmers.

#time-management #deep-work #productivity
9 min read
Productivity April 4, 2026

Dotfiles: How Shell Aliases and Config Files Multiply Developer Output

A practical guide to managing dotfiles, building useful shell aliases, and syncing your setup across machines with Git — with real examples that save hours.

#dotfiles #shell #cli #git
8 min read
Productivity March 29, 2026

Digital Declutter: A 30-Day Cleanup Guide

A structured 30-day plan to clean up your digital life. Files, apps, subscriptions, and even your codebase with AI-assisted workflows.

#digital-minimalism #self-improvement #productivity
10 min read
Dev March 27, 2026

Regex for Humans: A No-Fear Practical Guide

Start with 10 regex patterns you can use in 5 minutes. Progress to real log parsing, data cleaning, and validation with pitfalls to avoid.

#regex #reference #guide
10 min read
Dev March 24, 2026

HTTP Status Codes in Practice: 200 to 503

A practical guide to HTTP status codes with real server logs, when to use 301 vs 302, and what codes mean behind a CDN or load balancer.

#http #web #api #reference
9 min read
Dev March 22, 2026

Designing for the 8%: A Color Accessibility Guide

8% of men have color vision deficiency. Learn WCAG 2.2 contrast ratios, test with simulators, and grab 5 ready-to-use accessible palettes.

#accessibility #color #wcag #design
9 min read
DevOps March 19, 2026

Cron Expressions Demystified: Basics to Production

Learn cron syntax from five-field basics to timezone traps and real-world scheduling patterns. Includes 20 production-tested expressions.

#cron #scheduling #devops #reference
8 min read
Security March 17, 2026

QR Code Security: What to Know Before You Scan

QR phishing attacks rose 587% in 2023. Learn how QR codes work internally, what makes them exploitable, and how to scan safely.

#qr-code #security #phishing
7 min read
Dev March 14, 2026

How DNS Actually Works: Address Bar to Server

Trace a DNS lookup step by step with real dig output, resolver caching behavior, and what happens when DNS goes wrong.

#dns #networking #web
9 min read
Fun March 11, 2026

The Monty Hall Problem: When Intuition Fails

Why switching doors wins 2/3 of the time, backed by simulation data, Bayesian reasoning, and the real story behind the controversy.

#probability #statistics #psychology
7 min read
Productivity March 8, 2026

Keyboard Shortcuts: From Leader Key to Karabiner

Go beyond default hotkeys with Leader Key, Tuna, Karabiner-Elements, and AutoHotkey. Real configs, workflow demos, and when to use each tool.

#keyboard #macos #karabiner #productivity
10 min read
Dev March 5, 2026

JSON vs YAML vs TOML: How to Pick the Right Config Format

Compare JSON, YAML, and TOML side by side with syntax examples, parser benchmarks, and a decision table for when each format shines or breaks.

#yaml #json #toml #config-format +1
9 min read
Productivity March 2, 2026

Obsidian CLI Practical Guide: What Changed in 1.12 and How to Use It

An update-focused Obsidian CLI guide: what changed in recent 1.12 releases and how to apply the new commands in daily workflows.

#obsidian #cli #automation #pkm
11 min read
Productivity February 23, 2026

From Notes to Shipping: Building an Obsidian + MCP + Claude Code Operating System

A high-leverage operating model for combining Obsidian knowledge design, MCP context bridges, and Claude Code execution into one repeatable development loop.

#obsidian #mcp #claude-code #pkm +1
12 min read
DevOps February 22, 2026

Homelab Zigbee Coordinator Guide: ZBDongle-P vs ZBDongle-E vs SLZB-06 for Home Assistant + Zigbee2MQTT

A practical comparison of popular Zigbee dongles for Home Assistant homelabs, including architecture choices, model tradeoffs, and a setup checklist.

#homelab #zigbee #iot #home-assistant +1
12 min read
Productivity February 9, 2025

The Pomodoro Technique Isn't About Tomatoes: A Time Management Deep Dive

Beyond the basic timer: advanced strategies for the Pomodoro Technique that actually boost focus, backed by neuroscience and real-world experience.

#pomodoro #time-management #focus
7 min read
Security February 9, 2025

Password Entropy: Why 'Correct Horse Battery Staple' Beats 'P@ssw0rd'

Understanding password strength through information theory. Learn why longer passphrases are mathematically stronger than complex short passwords.

#password #security #cryptography
6 min read
Fun February 9, 2025

Why We're Bad at Estimating: The Psychology of Numbers

From lottery odds to project deadlines, our brains consistently fail at numerical reasoning. Explore the cognitive biases that make us terrible with numbers.

#psychology #cognitive-bias #statistics
6 min read
Image January 29, 2025

PNG vs JPEG vs WebP: Choosing the Right Image Format

Understand the differences between image formats and learn when to use each one for optimal quality and file size.

#image-optimization #webp #comparison
7 min read
Image January 28, 2025

The Complete Guide to Image Optimization for the Web

Learn how to optimize images for faster page loads, better SEO, and improved user experience with practical tips and free tools.

#image-optimization #web-performance #seo
8 min read