Tutorials
Showing 47 articles
HTML Entities Explained: Named, Numeric & When to Escape
A practical guide to HTML entities: named, decimal and hex references, the five characters you must escape, and the context rules that prevent XSS.
JSONPath Syntax Guide: Query & Filter JSON with Examples
Learn JSONPath syntax with copy-paste examples: root, recursive descent, wildcards, slices, and filter expressions. Test every query live in your browser.
PX vs REM vs EM: The Complete CSS Units Guide
px vs rem vs em explained: what each CSS unit means, when to use rem for accessibility, the em compounding trap, and a per-property cheat sheet.
How to Escape JSON Strings: Characters, Stringify & Pitfalls
How to escape a string in JSON: which characters need escaping, how it differs from JSON.stringify, JSON-in-JSON nesting, Unicode escapes, and common pitfalls.
Image to Base64 & Data URIs: When to Inline Images (2026)
Should you convert an image to Base64? See when data URIs help, the 33% size cost, CSS/HTML inlining, caching tradeoffs, and when a normal image file wins.
Code Minification Guide: CSS, JS & HTML Explained
What code minification is, how minifying CSS, JS, and HTML works, and why minify and gzip/brotli are different. Learn the order and minify your code free.
SQL Style Guide: Formatting Best Practices for 2026
A practical SQL style guide: keyword casing, indentation, JOIN/WHERE line breaks, naming rules, and dialect quirks, plus how to auto-format SQL free.
curl Cheat Sheet: 40+ Command Examples for HTTP & APIs
Complete curl cheat sheet for developers: GET/POST, headers, bearer auth, file upload/download, and API testing — 40+ copy-paste examples. Try our tools.
What Is Lorem Ipsum? Meaning, Origin & How to Use Placeholder Text
Lorem Ipsum explained: what the pseudo-Latin means, where it comes from, why designers use placeholder text, how to generate it anywhere, and when not to ship it. Try the free generator.
XML to JSON: Conventions, Pitfalls & Code (2026 Guide)
Convert XML to JSON the right way: how attributes, arrays, and namespaces map, why values stay strings, plus code for JavaScript, Python and the browser.
JSON to TypeScript: Generate Interfaces & Types (2026 Guide)
Convert JSON to TypeScript interfaces the right way: type inference rules, interface vs type, optional and union fields, plus pitfalls to avoid. Try it free.
OKLCH Color Space Explained — Why Tailwind v4 Adopted It
Why OKLCH became the design-system standard in 2024–2026. How it differs from HSL and LCH, with a worked HEX→OKLCH conversion.
SHA-1 vs SHA-256 vs SHA-512: 2026 Hash Algorithm Guide
SHA-1, SHA-256, SHA-384, SHA-512, and SHA-3 compared on security status, output size, performance, and real use cases. Includes a decision tree and common pitfalls.
UTF-8 vs UTF-16 vs Unicode Encoding Guide for Developers
UTF-8 vs UTF-16 vs UTF-32 explained for developers — codepoints, surrogate pairs, BOM, MySQL utf8mb4 traps, and JS length lies. Learn how to pick the right encoding.
WCAG Color Contrast Ratio Guide: AA, AAA, and APCA Explained
Master WCAG contrast ratios. Learn 4.5:1 AA and 7:1 AAA thresholds, the APCA Lc algorithm, color blindness, and how to fix failing combinations.
camelCase vs snake_case vs kebab-case: 2026 Naming Conventions Guide
camelCase vs snake_case vs kebab-case 2026 — 6 case styles, 7-language decision matrix, acronym rules, URL slug SEO, and 6 conversion pitfalls.
Character & Word Limits 2026: Twitter, SMS, SEO, Instagram Guide
Character and word limits 2026 across Twitter, SMS GSM-7/UCS-2, SEO meta, Instagram, and LinkedIn — counting math plus live progress bars for 6 platforms.
Crontab Cheat Sheet: 50+ Cron Expressions and Modern Scheduler Guide
Crontab cheat sheet: 50+ copy-paste cron expressions, field-by-field syntax, the OR-trap, timezone fixes, plus Kubernetes/GitHub/AWS comparisons.
Text Diff Online: How to Compare Two Texts (Algorithm + 6 Use Cases)
Free text diff online — instant side-by-side + unified diff, no upload. Learn the LCS/Myers algorithm, text vs JSON diff, and 6 code-review use cases.
Flatten Nested JSON to CSV: 5 Strategies & Decision Matrix
Compare 5 strategies to flatten nested JSON to CSV: dot notation, indexed arrays, explode rows, stringify. Decision matrix for Excel, Pandas & BigQuery.
Regex cheat sheet: metacharacters, groups, and lookarounds
Regex cheat sheet: metacharacters, quantifiers, anchors, groups, lookarounds, plus 15+ JavaScript and Python patterns and concrete fixes for catastrophic backtracking.
HTTP Status Codes Cheat Sheet: Every Code Explained (1xx-5xx)
Complete HTTP status codes reference: 1xx through 5xx explained with real examples, common mistakes (401 vs 403, 301 vs 302), and SEO impact. Try our tools.
JSON Schema validation in 2026: Ajv, Python, browser guide
Validate JSON against a schema in Node, Python, and the browser. Draft 2020-12 essentials, real API patterns, and copy-paste examples for 2026. Try free.
WebP vs AVIF vs JPEG: Which Image Format Wins in 2026?
AVIF is 20–30% smaller than WebP and 30–50% smaller than JPEG, but encodes 5–20× slower. 2026 browser support, real benchmarks, and <picture> fallback patterns. Try free.
Static vs Dynamic QR Codes — Why Yours Stops Working
Dynamic QR codes expire when their redirect service shuts down. Static QR codes never expire. Why the difference matters and how to choose.
How to Ignore Timestamps and IDs in JSON Diff (Without Writing jq)
API regression diffs are 80% noise — timestamps, request IDs, UUIDs that mutate per-request. Use Extended JSON Pointer patterns to surface only meaningful changes.
The YAML Norway Problem and JSON-YAML Differences for Engineers
Why YAML reads "no" as false. Real K8s outages from string quoting. JSON vs YAML choices, indent rules & K8s manifest conversions explained.
cm to inches: exact formula, height & screen charts (2026)
Convert cm to inches (centimeters to inches) with the exact 1 in = 2.54 cm factor. Mental-math, height, screen, paper charts plus code. Free in browser.
ml to oz: US & UK fluid ounce formulas, charts (2026)
Convert ml to fl oz with exact NIST factors. US (29.5735), UK (28.4131), FDA label 30 mL rounding. Try the free volume converter in your browser.
kg to lbs: NIST formula, mental math and quick charts (2026)
Convert kilograms to pounds with the NIST-exact factor (1 kg = 2.20462 lb). Mental-math tricks, body-weight, luggage and medical-dose charts. Free.
Temperature Conversion Formulas: Celsius, Fahrenheit, Kelvin
Exact temperature conversion formulas for Celsius, Fahrenheit, Kelvin and Rankine with code in 5 languages, weather API patterns, common pitfalls and reference tables.
Bitwise Operations Explained: AND, OR, XOR, Shifts, and Masks
Master bitwise operations with hands-on examples: AND, OR, XOR, shifts, two's complement, bitmasks, and feature flags, with code in JS, Python, Go, and C.
jq Cheat Sheet: 30 Real-World JSON Command-Line Patterns
Master jq with 30 battle-tested patterns for filtering, transforming, and extracting JSON on the command line — from kubectl and AWS to log files.
Number Base Conversion Guide: Binary, Hex, Octal & Decimal
A developer's guide to binary, hex, octal & decimal conversion — step-by-step methods, code examples in JS/Python/Go/C, and real-world use cases. Free online converter included.
URL Encoding & Decoding: A Developer's Guide to Percent Encoding
RFC 3986 rules, encodeURI vs encodeURIComponent, UTF-8 byte mapping, and code examples in JS, Python, Go & Java. Try our free online tool.
Unit Conversion Guide: Length, Weight, Temperature & Volume
Metric-to-imperial conversion with exact formulas, code examples & quick-reference tables for length, weight, temperature and volume.
CSV to JSON Conversion: Methods, Pitfalls & Code Examples
Convert CSV to JSON (and back) with Python, JavaScript & CLI tools. Covers encoding traps, type coercion and streaming large files.
MD5 vs SHA-256: Hash Algorithm Comparison for Developers
Compare MD5, SHA-1, SHA-256 and SHA-512 on security, speed and output size. Learn which hash to choose for checksums and password storage.
UUID v4 vs v7 vs ULID vs Snowflake: ID Guide (2026)
UUID v4, v7, ULID, Snowflake ID and NanoID compared on database performance, sortability, storage size and ecosystem support with code examples.
What Is a UUID? Guide to Format, Versions & Use Cases
UUIDs from the ground up: 128-bit structure, hex format, how v1/v3/v4/v5/v7 work internally, collision math, real-world use cases and code examples.
What Is Base64 Encoding? A Beginner's Guide
New to Base64? Learn what Base64 encoding is, how it works step by step, and why developers use it — a beginner-friendly introduction with clear examples.
Unix Timestamp Guide: Precision, Timezone & DST Tips
Unix timestamps explained: epoch origins, seconds/ms/us conversion, timezone handling, DST pitfalls, and code examples in JS, Python and Go.
Image Compression: Browser vs Node.js Solutions
Compare Squoosh, Sharp, browser-image-compression and more — learn when to compress client-side vs server-side, with benchmarks and code examples.
From JSON5 to JSONC: A More Forgiving JSON Formatting Guide
Learn JSON5 vs JSONC differences, format config files with comments, and integrate formatters into your CI pipeline — with real-world code examples.
What Exactly Lives Inside a PostgreSQL timestamp Column?
A plain-English guide to how PostgreSQL stores timestamp vs timestamptz, why timezones bite, and how to choose the right type for your use case.
Advanced Base64: MIME, Data URLs, Performance & Security
Implement Base64 in JavaScript and Python, optimize data URLs, choose standard vs URL-safe variants, and avoid common security pitfalls.
Essential Developer Tools for Encoding & Hashing (2026)
Compare 9 free browser-based developer tools for Base64, JSON, UUID, hashing, image compression and unit conversion — all 100% client-side.