The pricing is currently per user, since I've envisioned it as a tool that you'd invite all your developers onto. For the most part, this has been the case, but there are some companies using it heavily on the server-side and only inviting a small number of users.
To account for this, I've considered charging a small amount per access key (say $2/mo for a base plan) instead of per user. A typical app has an access key for each developer working on it, plus one per server, so for a team of 5 this would work out to ~16/app/month (assuming test, staging, and production server environments; some have more). Most teams seem to have at least a few apps; some have as many as 10.
The good thing is this would scale up with usage, starting very low and then getting pretty substantial as you get more and more use out of the product. The bad thing is... it would scale up with usage, and therefore might disincentive heavy use.
Any thoughts?