The advice here is sage. If you run a platform-type SaaS business (not necessarily PaaS but more like SaaS with multiple functional use cases, which the OP calls the API business), make sure to read the OP.

To me, this one resonated best:

"APIs have a particularly tough marketing challenge in that the product can have a ton of varying use cases. You need different messaging to multiple customer segments each with their own use cases and needs."

In terms of "doing things that don't scale early on", this is _the_ thing API-as-a-Service companies ought to do. Your users won't build reference apps for you. You need to build them for your customers and make them very easy to use. This amounts to what enterprise software marketers call "solution selling."

Disclosure: I lead marketing at Treasure Data, an early Clearbit customer.