I am looking for a domain name registrar which provides an api for registration. I want to register domain names programmatically. I don't want registrars which sell packages for resellers or affiliates or merchants where you have to pay some amount upfront or register a minimum number of domains/month. I just want a free use of the api. Otherwise I will have to do it through clunky screen scraping. I expect to register 0-20 domains/month. The domain registration will be part of an automated web hosting ordering system.
If you're willing to fund your account with at least $50 (to be used for purchasing domains), Moniker has an API. Email Don Lyons (firstname AT moniker.com), I'm sure he'll send you the info ASAP.
PS: You may be able to find better APIs and prices elsewhere, but Moniker has a reputation of never losing a domain and bending over backwards to recover stolen domains and such.
Gandi offers this, and has extensive documentation explaining their API here: http://doc.rpc.gandi.net/domain/
You can programmatically register, manage, and transfer domains with their service. No affiliation with them, except as a happy customer.