I think you may be underestimating the need for an API. We're a small company (17 employees) and we wouldn't consider it without an API.

Remember lots of systems generate leads/customers, so if you don't want to provide tools for all those various systems, you need to offer an API.

Also on your sign up page, there's a typo:

"Wobaka cost way less than lost deals" should be "Wobaka costs way less than lost deals"

Unless Wobaka is plural?