Hey Product Hunt! I'm Kuper, the solo dev behind devkits. **Why I built this:** Every time I needed a JSON formatter or a JWT decoder, the top Google result was plastered with ads and a "pro plan" upsell. I wanted tools I could actually trust — and ones where I could open DevTools, check the network tab, and see zero outbound requests. So I built 178 of them. Every one runs 100% client-side. No uploads, no accounts, no tracking. **My favorite technical detail:** The PrefetchLink component (open source in the repo). Next.js 15's `` disables both viewport AND hover prefetch — which kills the instant-navigation feel on slow connections. My wrapper uses `router.prefetch()` on hover/focus/touchstart, sharing one global Set for dedup. If you build with Next.js, steal this pattern. **Ask:** Try decoding a JWT, converting a CSL to JSON, or generating an OTP. If you find a tool you wish existed, tell me in the comments — I add new tools every week. Happy to answer questions!

devkits.vip

178 Free Developer Tools — 100% Local, No Upload, No Sign-up

178 Free Developer Tools — 100% Local, No Upload, No Sign-up