Guides
In-depth guides to JSON, regular expressions, encodings, and the calculators and design tools on AnyTools.
- Complete Guide to JSON in 2026Deep dive into JSON: history, syntax, variants (JSON5, NDJSON, BSON), validation, performance, and security. With practical examples and 10+ FAQs.18 min read
- Regex Mastery: From Beginner to WizardMaster regular expressions: finite automata theory, JS flags, 30 common patterns, lookahead/lookbehind, catastrophic backtracking, Unicode, and performance.20 min read
- Encoding Encyclopedia: Base64, URL, JWT, and BeyondComplete reference for Base64, URL encoding, HTML entities, JWT, Unicode, and character sets. Encoding vs encryption clarified, decision tree included.20 min read
- Free Finance Calculators — Mortgage, Loan, Tip, Compound InterestA practical guide to free online finance calculators: tip splitter, compound interest, percentage discounts, and more. Pure-browser, no signup, no tracking.7 min read
- BMI, Calorie & Fitness Calculators — A Practical GuideHow to use BMI, BMR, and fitness calculators correctly. Metric vs imperial inputs, WHO categories, and where the formulas come from.6 min read
- Everyday Utility Tools — Age, Unit Converter, GPA, and MoreSmall tools that save you a Google search: age in days, unit converter, GPA calculator, percentage math, reading time, and word count.5 min read
- Color Converter & WCAG Contrast — A Designer's GuideHEX, RGB, HSL conversion plus WCAG 2.1 AA/AAA contrast ratios — what they mean, when each test matters, and how to read the numbers.6 min read