Local-first developer toolkit
Most work runs in your browser

This site started from a daily frustration: developers format JSON, decode JWTs and convert data every day, yet most online tools either upload your pasted content to their servers or bury the tool under layers of ads. Handing text that contains internal hosts, tokens or customer data to a stranger's server is itself a security risk.

ToolVault's answer is "local-first": most of the 189 tools compute in your browser; the API Tester may optionally forward via this site's /api/proxy; in-site feedback is sent only when you submit it. The site works offline (PWA). Privacy is the default architecture — you can cross-check Network traffic against the Privacy Policy in DevTools.

On content: every troubleshooting article comes from a real development scenario — what the error looks like, the root cause, the diagnostic order, and how to prevent it. The site now carries 174 bilingual technical articles covering JSON, regex, network connections, Docker, Chinese national cryptography and more, each ending with an actionable checklist.

On engineering: 1,100+ automated unit tests guard tool correctness, and every new tool ships through full functional testing and bilingual proofreading. Tools and articles keep rolling — if you want a tool we don't have, or hit an error we haven't covered, tell us via the email below.