Use API Canvases. Find the right value proposition to your API. Define impact to business model.
Continue where service design left off and look at the "jobs-to-be-done" or tasks to be performed. Make sure you take the customer's view point.
Find all the APIs and other services needed to support the customer journey and bring specific value to the users (the end-users and the developers using the APIs)
Pick one API at the time for this canvas. Who else would be able to use it with the same value proposition? Create a business model for that API.
What APIs and other services you will need to bring gains or relieve pains from your users?
The Value Proposition Canvas is split into two parts, the API Consumer View and API Provider View.
Start with the API Consumer View. Think like the product managers and software developers of the companies/teams using your API.
Start from the right and work to the left.
It's important your team fills in the API Consumer view first. This will help innovate new ideas, focus on the exact behaviour, features and help needed and avoid building features that are not important.
Remember to validate the assumptions by asking needs from real potential API consumers.
Who wants to use your API, how do you collaborate with them, what is the revenue or other value and what exactly do you need to build, what you don't have? And with what costs?
The API Canvas consists of nine areas that have almost the same titles as in Business Model Canvas.
Start from the right and work to the left.
API Business Model Canvas is the master document for next phases of the method. You should share the API Canvas with all relevant stakeholders. This includes external developers and other partners you need to work with.