DNS Toolkit is part of DevStudio — a free, in-browser collection of developer utilities that work without sign-up, installation, or any backend service. A/AAAA/CNAME/MX/TXT/NS records, propagation across public resolvers, NS trace, reverse DNS, ASN lookup, all running entirely on your device. Because the page never uploads what you paste, you can run sensitive payloads, configuration files, secrets, or production data through it with confidence: nothing leaves your browser tab. Use DNS Toolkit for ad-hoc debugging, code review, log triage, release prep, learning a new format, or as a quick scratchpad while you build. If you use this tool a lot, pair it with Mail Diagnostics, Web Probes, Domain Diagnostics, and the rest of the DevStudio toolkit for related developer workflows.