Add DevToolBox - 100+ browser-based developer utilities

[Rih0z]

What is DevToolBox?

DevToolBox is a collection of 100+ free, browser-based developer tools that:

• Require no sign-up, no login, no installation
• Process all data locally in the browser (zero data transmitted to servers)
• Support Japanese and English interfaces

Tool categories include:

• Encoding/Decoding: Base64, URL, HTML entity, JWT decoder
• Data Format Conversion: JSON ↔ CSV ↔ XML ↔ YAML ↔ TOML
• Hash Generation: MD5, SHA-1/256/512, bcrypt, HMAC
• CSS Utilities: Color converter, gradient generator, unit converter
• Regex Tester: Real-time pattern matching with explanation
• Network Tools: IP lookup, DNS lookup, HTTP header viewer
• And many more...

Why it fits this list

It meets the contributing guidelines:

• ✅ Solely web-based
• ✅ Freeware (completely free, no premium tier)
• ✅ No sign-up, download, or installation required

Suggested placement

Under Web-based Tools > Transformation as it primarily provides data conversion and encoding/decoding utilities.

Source code: https://github.com/Rih0z/devtoolbox

[github-actions]

Hey Rih0z! Thanks for your submission! 🚀

To keep awesome-devtools instantly accessible for everyone, all tools must be:

• Browser-based — no downloads or native app installs
• Direct link — goes straight to the tool (not a multi-tool landing page)
• 100% free — no signups, trials, paywalls, or usage limits

Please make sure your PR meets these criteria. It may take some time for your submission to be reviewed — you can occasionally comment with a "bump" to bring more attention to it.

Thanks for contributing! 🙌

[moimikey]

Thanks for your submission! However, we noticed that you have 3 open PRs all proposing the same tool (DevToolBox): #318, #328, and #331.

Please consolidate these into a single PR to avoid confusion and keep the review process clean. We're closing this one along with the others — feel free to open one new PR once you're ready.

Also, please make sure your submission follows the contribution guidelines before resubmitting, including:

• The tool must be solely web-based (no download or install required)
• It must be freeware (completely free, no premium tier)
• No sign-up, download, or installation required

Thanks!