Resolver is an incredibly simple REST-style DNS resolver web service, built with Sinatra and Net::DNS.
It returns a JSON array of relevant results (or a JSONP packet if given a callback query string parameter) for the given domain and record type. The default record type is A for domains, but other types can be requested (see examples below); IP addresses perform a reverse lookup.
The service runs on Heroku, and makes use of HTTP caching on all requests (requests are cached for 5 minutes).
GET /tim.bla.ir
GET /google.com?callback=announce
GET /google.com/MX
GET /www.google.com/CNAME
GET /74.125.148.11
Resolver was developed by Tim Blair and has been released under the MIT license as detailed in the LICENSE file that should be distributed with this library; the source code is freely available.