Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
Per Mille Sign is a reserved HTML characters and special typographic symbols. This HTML entity enables web developers to display this character reliably across all browsers without encoding issues.
U+02030
‰
\2030
Use the HTML entity to safely display reserved HTML characters in web content. For example, if you want to show a code snippet on your page, use <div> instead of raw <div> to prevent the browser from interpreting it as HTML.
Mistake: Forgetting to encode special HTML characters in user-generated content
Fix: Always encode &, <, >, ", and ' as HTML entities when displaying user input to prevent XSS attacks and rendering issues.
Mistake: Using HTML entities inside <script> or <style> tags where they won't be parsed
Fix: HTML entities are only parsed in HTML context. In JavaScript strings, use escape sequences like \x26 instead of &.
Select any code to highlight it before copying.
| Unicode | U+02030 |
|---|---|
| Hex Code | ‰ |
| HTML Code | ‰ |
| HTML Entity | ‰ |
| CSS Code | \2030 |
| Windows Shortcut | Alt 0137 |
| Mac Shortcut | ⇧⌥E |
Blog
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
A practical decision guide to choosing the right hash algorithm: MD5, SHA-1, SHA-2, SHA-3, bcrypt, argon2, PBKDF2, and SRI, with comparisons and clear recommendations.
Aug 08, 2026
A thorough, practical comparison of hand-written CSS and Tailwind CSS: learning curve, maintainability, performance, team workflows, and when each approach wins.
Aug 08, 2026
Learn practical, step-by-step techniques to improve LCP, INP, and CLS on your website. A developer-focused guide with real measurements and fixes.
Aug 08, 2026
Learn practical, production-ready ways to use Base64 encoding: data URLs for images, JWT payloads, API tokens, and email attachments, with real code examples.
Aug 08, 2026
Learn how AES encryption works, the differences between AES-128, AES-192, and AES-256, and how to encrypt and decrypt data online.
Jun 23, 2026