Developer Guides
100 articlesIn-depth tutorials and best practices for the technologies behind your favorite developer tools — hashing and password storage, image and PDF internals, HTTP and DNS, regular expressions, and the browser APIs the tools are built on.
Written and edited by Necmeddin Cunedioglu. Every article is original to this site, carries a publish date, and is corrected in place when something changes — see the editorial policy.
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Comprehensive Guides
Core Web Vitals in 2026: The Complete INP, LCP, and CLS Optimization Playbook
A practical guide to Core Web Vitals now that INP replaced FID: what LCP, INP, and CLS measure, the thresholds that matter, and how to pass each one.
Generative Engine Optimization (GEO): How to Get Cited by AI Search in 2026
A practical guide to Generative Engine Optimization: how ChatGPT, Google AI Overviews, and Perplexity pick and cite sources — and how to earn the citation.
Prompt Engineering for Developers: Patterns That Actually Work in 2026
A no-hype guide to prompt engineering for real LLM apps: roles, few-shot, chain-of-thought, structured output, RAG, and evaluation patterns that work.
PDF vs DOCX: Structural Document Formats Comparison
PDF vs DOCX architecture: fixed-layout coordinate systems vs reflowable XML text nodes, plus font embedding — and what each format is really for.
Developer Generators: The Tools That Save You Hours Every Week
The generators every developer needs — UUIDs, passwords, QR codes, favicons, meta tags, robots.txt, and .gitignore — and when, why, and how to use each.
The Complete Guide to Browser-Based Image Editing
Image processing in the browser: Canvas drawImage(), resampling algorithms, format conversion, EXIF extraction, local PDF generation — plus WebAssembly, Web Workers, why local beats the cloud on latency, and how to verify a tool is really client-side.
Time & Date in Programming: The Complete Developer Guide
A developer's guide to handling time: the Unix epoch and Year 2038, IANA timezones and DST, JavaScript Date traps, ISO 8601, cron scheduling, TIMESTAMPTZ vs DATETIME, forcing TZ=UTC, and a pre-deploy checklist.
HTTP Status Codes: The Complete Guide for Developers
A complete guide to HTTP status codes: 401 vs 403, the SEO impact of 301 vs 302, 409 for optimistic locking, and how to monitor 5xx errors properly.
CSS Color Systems: A Complete Guide for Developers
Master CSS color formats — HEX, RGB, HSL, and Color Level 4: when to use each, how to build consistent palettes, and what perceptual uniformity means.
Web Security: Encoding and Hashing Guide
Encoding vs hashing vs encryption: when to use Base64, SHA-256, bcrypt, AES-256-GCM and HTML entity encoding — with decision trees, the Kubernetes Secrets and JWT misconceptions, and working replacement code.
Regular Expressions: The Complete Guide
The complete regex reference: syntax, quantifiers, anchors, groups and lookarounds, NFA backtracking and ReDoS, per-language gotchas in JS/Python/Java, plus tested patterns for email, URLs, IPs and dates.
JSON: The Complete Developer Guide
Everything about JSON: syntax and the six types, reviver/replacer, V8 parsing internals, BigInt precision loss, streaming large payloads, JSON Schema validation with Ajv, JSONPath querying, and REST API practice.
AI Tools
View allNetwork & API
View allWeb Security
View allbcrypt vs SHA-256: Password Hashing Compared
Why SHA-256 is wrong for passwords and bcrypt is right: salting, key stretching, and modern password-hashing best practices with real benchmarks.
XSS Prevention with HTML Entity Encoding
The engineering guide to stopping XSS: context-aware HTML entity encoding, Content Security Policy nonces, DOM-based attacks, and Trusted Types.
Security & Cryptography
View allImage Processing
View allEncoding
View allText Processing
View allWeb Performance
View allTime & Date
View allCron Expression Guide: Syntax and Examples
Master cron syntax with examples: 5-field and 6-field formats, special characters, DST anomalies, and platform differences for Linux, AWS, and Kubernetes.
Date Formatting for Developers: ISO 8601, Intl API, and Cross-Language Patterns
Formatting dates and times in JavaScript, Python, and SQL: ISO 8601 strictness, Intl.DateTimeFormat, timezones, locale-aware output, and common bugs.
CSS & Design
View allWCAG Color Contrast: Accessibility Guide for Developers
WCAG 2.1 color contrast: the math of relative luminance, how to test ratios, what APCA (WCAG 3.0) changes, and how to fix common accessibility issues.
HEX vs RGB vs HSL: Which Color Format Should You Use?
HEX vs RGB vs HSL vs modern OKLCH in CSS: conversion formulas, design-system examples, accessibility notes, and browser support at a glance.
CSS Color Systems: A Complete Guide for Developers
Master CSS color formats — HEX, RGB, HSL, and Color Level 4: when to use each, how to build consistent palettes, and what perceptual uniformity means.
Color & CSS
View allDeveloper Tools
View allWeb Development
View allHTTP Status Codes: The Complete Guide for Developers
A complete guide to HTTP status codes: 401 vs 403, the SEO impact of 301 vs 302, 409 for optimistic locking, and how to monitor 5xx errors properly.
Favicon & PWA Icons: The Complete Setup Guide
A complete guide to favicons, Apple Touch Icons, and PWA manifests: SVG dark-mode favicons, Android maskable safe zones, and the iOS white-screen fix.