StackUtils Blog
Practical deep dives on the technologies behind our tools — written by developers, for developers.
When two JSON documents diverge, you need a reliable way to compare, diff, and merge them. This guide covers RFC 6902 JSON Patch, RFC 7396 JSON Merge Patch, deep equality, and practical diffing strategies.
Read articleQR codes are everywhere, but few developers know what's actually inside them. This guide explains the data encoding layers, error correction levels, version sizes, and how to generate QR codes programmatically.
Read articleCSS supports a dozen color formats and choosing the wrong one makes your code harder to maintain. Learn when to use HEX, RGB, HSL, oklch, and CSS custom properties — with conversion formulas and practical tips.
Read articlecURL is installed on virtually every developer machine, yet most only use it for basic GET requests. This guide covers authentication, custom headers, POST bodies, file uploads, cookies, and how to convert cURL commands to code.
Read articleHTTP headers control caching, security, CORS, content negotiation, and more. This guide covers the 20 most important headers with real-world examples and the common mistakes that cause bugs in production.
Read articleWeak passwords are the most common entry point for breaches. This guide covers entropy, password policies, secure storage with bcrypt and Argon2, and how to build a compliant password generator.
Read articleHashing is not encryption — and confusing the two causes serious security bugs. Learn how SHA-256, MD5, and bcrypt work, when to use each, and why you should never store plain-text passwords.
Read articleUsing production data in development is a privacy risk. Learn how to generate realistic fake data for testing — covering popular libraries, patterns, seed strategies, and GDPR compliance.
Read articleMarkdown is the universal format for READMEs, docs, and notes. This complete reference covers headings, lists, code blocks, tables, and GitHub-Flavored Markdown (GFM) extensions.
Read articleUnformatted SQL is a maintenance nightmare. This guide covers indentation conventions, JOIN alignment, CTE style, and how consistent formatting prevents logic bugs in complex queries.
Read articleEvery developer has seen %20 in a URL and wondered what it means. This guide covers percent-encoding, RFC 3986, the difference between encodeURI and encodeURIComponent, and when to use each.
Read articleCron syntax looks cryptic at first. This guide breaks down all five fields, special characters, and real-world scheduling patterns — from every-minute jobs to complex monthly runs.
Read articleJWT tokens are in every Authorization header, but most developers never look inside them. Learn the header.payload.signature structure, common claims, signing algorithms, and the security mistakes to avoid.
Read articleLearn how to write effective prompts for AI coding assistants. Covers few-shot examples, chain-of-thought reasoning, role prompting, and 10 real patterns that work in production.
Read articleGitHub Copilot, Cursor, Claude, ChatGPT, Gemini — the AI landscape for developers has exploded. This guide compares the top tools, their strengths, pricing, and the workflows they fit best.
Read articleEver wondered why your CSS rule isn't applying? The answer is almost always specificity. Learn the (a, b, c) scoring system, !important, and how to win specificity battles cleanly.
Read articleNot all unique identifiers are created equal. Understand UUID v4, v7, ULID, and CUID — and how each choice affects your database performance.
Read articleRegex can feel like magic — or a nightmare. This guide covers character classes, quantifiers, groups, and real-world patterns for email, URL, and date validation.
Read articleBase64 is everywhere — JWT tokens, CSS data URIs, email attachments. This guide explains how the algorithm works and when you should (and shouldn't) use it.
Read articleJSON is the lingua franca of web APIs. Learn its syntax, data types, common errors, and how it compares to XML — with real-world examples.
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