About
Última actualización: 2026-08-13
DevTools Hub is a free collection of utilities built so that the work developers and knowledge workers repeat every day can be finished inside the browser. All 33 tools run the moment you open the link — no install, no account.
1. What this site does
Formatting JSON, decoding a JWT, testing a regular expression, generating a hash, converting between PDF and images — small jobs you need several times a day and usually solve by searching and opening whichever site comes up first. They are all collected here.
Tools are split between engineering utilities and text or document work, and every tool page carries instructions, frequently asked questions and the background worth knowing. The aim is that you leave understanding why the tool behaves the way it does, not just having used it.
2. Why it was built
Something always nags when using an online converter: you have no idea where the data you pasted went. Uploading a production JWT, a CSV full of customer records or a scanned contract to an unfamiliar site is a real way to cause an incident.
So this site was designed from the start without any server that could receive your input. Every conversion and calculation runs inside your browser and files are never uploaded. Open your browser's network tab while working and you can confirm for yourself that no request carries what you typed.
3. How it is built
The site ships as static files with no backend or database that processes input. Each tool's conversion logic is covered by unit tests, and before every deploy a real browser opens every tool page to confirm it still works.
The MD5 implementation in the hash generator is checked against the official RFC 1321 test vectors; the PDF writer is verified by parsing the files it produces back again. Correctness is confirmed by tests rather than by eye.
4. Running costs and advertising
Every tool is free and there are no plans to charge for any of them. Hosting and domain costs are covered by advertising shown on the pages.
Ads are placed only in areas clearly separated from the content; they never obscure a tool or push you toward clicking. How advertising vendors use cookies is described in the privacy policy.
5. Languages
The site is currently available in Korean, English, Japanese and Spanish. Your language is selected automatically from your browser settings and can be changed from the menu at the top.
A language is only published once its translation is complete, so new ones appear as they become ready.
6. Contact
Bug reports, suggestions for new tools and partnership enquiries are all welcome at the address below. Reports that a result is incorrect are looked at first.
asolv.kr@gmail.com