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 allJWT Security: What's Safe to Decode, and What You Should Never Paste Online
A JWT is just Base64 — anyone can read it. How to inspect tokens safely, why pasting a live token into a random site is risky, and how signatures protect you.
Are Online PDF Tools Safe? Server Upload vs In-Browser Editing
What really happens when you upload a PDF to an online tool — server retention, breach exposure, jurisdiction — and how in-browser editing avoids it.
Security & Cryptography
View allImage Processing
View allHow to Redact a Screenshot or Photo (and Not Leak the Hidden Parts)
How to redact images safely: black box vs blur vs pixelate, why destructive redaction matters, stripping metadata, and a check that nothing was uploaded.
AVIF vs WebP vs JPEG XL: Choosing the Right Image Format in 2026
A practical comparison of AVIF, WebP, JPEG XL, and the classics (JPEG, PNG, GIF): compression, browser support, and exactly when to use each.