Ignore the people saying "don't do this" and instead read "Monetizing Innovation" (https://www.amazon.co.uk/Monetizing-Innovation-Companies-Design-Product/dp/11

Ignore the people saying "don't do this" and instead read "Monetizing Innovation" (https://www.amazon.co.uk/Monetizing-Innovation-Companies-Design-Product/dp/1119240867 https://www.amazon.co.uk/Monetizing-Innovation-Companies-Des...) to get some guidance. It's difficult to summarise the key lessons but you need to consider things like: * What does having an API allow your customers to do? * How valuable is that? * Are they willing to pay for it? * How do you align payment to the value? * Is an API considered "table stakes?" The book I linked goes into more detail so I really encourage you to read it. You can skip over the organisational changes it recommends, just the principles of pricing are good enough for your use case.