I’d like to vote for Rackpace which has an API; https://developer.rackspace.com/docs/cloud-dns/v1/. Having support for them, or the manual option, would allow us to use wildcard certificates. Are you accepting pull requests for new DNS providers?
@davecanderson thanks, yes we are accepting pull requests. Our current DNS providers can be found here: https://github.com/webprofusion/certify/tree/development/src/Certify.Providers/DNS and the main requirements are that the code is yours (or is MIT licensed and copied with permission) and that it has minimal dependencies (Azure and AWS both have NuGet packages, but we don’t want more if we can avoid it).
The DNS provider just needs to implement the IDnsProvider interface. The general operations an API has to implement are creating TXT a record, deleting a TXT record and listing zones.
Work has started on the scripting option (run your own script to create/delete records) and will be followed by a manual options (generally only useful if you’re managing a handful of domains).