28 developer guides, tutorials, and references — all free.
Learn how to validate JSON data, fix common syntax errors, and understand why JSON validation matters for APIs, configs, and data exchange. Includes practical examples and free tools.
Read articleLearn the correct regex pattern for email validation, why simple patterns fail, and how to implement email validation in JavaScript, Python, and PHP. Test patterns live with our free regex tester.
ReadMaster Unix file permissions with this complete chmod guide. Learn what 755, 644, and 777 mean, how to read symbolic notation, and security best practices. Includes an interactive calculator.
ReadLearn what Base64 encoding is, how the algorithm works step by step, and when to use it in web development. Covers data URIs, JWT tokens, email attachments, and API authentication with code examples in JavaScript and Python.
ReadCompare MD5 and SHA-256 hash functions side by side. Learn the differences in security, speed, output size, and when to use each — with practical examples for checksums, passwords, digital signatures, and blockchain.
ReadCompare JSON and YAML side by side. Learn the key differences in syntax, features, use cases, and when each format is the better choice for configuration, APIs, and data exchange.
ReadCompare UUID v4, UUID v7, ULID, and NanoID. Learn the differences in randomness, sortability, size, and performance. Choose the right identifier for your database and API.
ReadMaster cron expression syntax with this complete guide. Learn the 5-field format, special characters, common schedules, and troubleshooting tips with practical examples for Linux, AWS, and Kubernetes.
ReadLearn the differences between px, rem, and em in CSS. Understand when to use each unit for fonts, spacing, and responsive layouts. Includes practical examples and accessibility best practices.
ReadCompare WebP, AVIF, and PNG image formats. Learn compression ratios, quality differences, browser support, and when to use each format for optimal web performance.
ReadThe 20 most useful regular expression patterns for email, URL, phone, date, IP address, password, and more. Copy-paste ready with explanations and live testing.
ReadLearn how JSON Web Tokens work, their three-part structure, common claims, security best practices, and when to use JWTs vs sessions for authentication.
ReadLearn what URL encoding (percent-encoding) is, which characters need encoding, the difference between %20 and +, and how to encode URLs in JavaScript, Python, and PHP.
ReadUnderstand the differences between HEX, RGB, and HSL color formats. Learn when to use each, how to convert between them, and practical tips for CSS color management.
ReadLearn WCAG contrast ratio requirements for AA and AAA compliance. Understand how to check, fix, and design accessible color combinations for text, buttons, and UI elements.
ReadLearn what Unix timestamps are, why developers use epoch time, how to convert between timestamps and dates, and common pitfalls with timezones and the Year 2038 problem.
ReadThe complete Markdown syntax reference. Covers headings, bold, italic, links, images, code blocks, tables, task lists, and GitHub Flavored Markdown extensions.
ReadLearn when to use camelCase, snake_case, kebab-case, PascalCase, and CONSTANT_CASE. Covers conventions for JavaScript, Python, CSS, SQL, APIs, and file naming.
ReadLearn what makes a password strong, how password entropy works, why length beats complexity, and modern best practices from NIST. Includes examples of strong vs weak passwords.
ReadLearn how to create QR codes for URLs, Wi-Fi passwords, email, phone, and text. Understand static vs dynamic QR codes, sizing, scanning tips, and best practices.
ReadReduce image file sizes by 60-80% without visible quality loss. Learn compression techniques, format selection, responsive images, lazy loading, and Core Web Vitals best practices.
ReadLearn regex patterns for validating US, UK, international, and E.164 phone numbers. Understand formatting variations, country codes, and when to use regex vs libraries.
ReadMaster CSS gradients with practical examples. Learn linear-gradient, radial-gradient, and conic-gradient syntax, color stops, repeating gradients, and creative design patterns.
ReadTroubleshoot the 10 most common JSON syntax errors: trailing commas, single quotes, unquoted keys, unexpected tokens, and more. Practical fixes with examples.
ReadCompare two texts or files to spot every difference. Learn online diff tools, command-line diff, VS Code comparison, Git diff, and when to use each method.
ReadLearn how to use MD5, SHA-256, and SHA-512 checksums to verify downloaded files haven't been corrupted or tampered with. Step-by-step for Windows, Mac, and Linux.
ReadLearn SQL formatting standards that make queries readable and maintainable. Covers indentation, keyword casing, JOIN alignment, subquery formatting, and team style guides.
ReadEverything about Lorem Ipsum: what it is, why designers use it, when NOT to use it, and 8 creative alternatives. Plus how to generate the right amount for any design.
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