I would be interested in seeing more of these API Gateways offer monetization / billing capabilities in their dev portal. So far I've only seen Apigee[1] and WSO2[2] offer this. Azure appears to have this "planned" in their product roadmap[3] while AWS uses their marketplace[4].

[1] https://cloud.google.com/apigee/api-management/monetize-apis...

[2] https://wso2.com/blogs/thesource/2019/10/wso2-api-cloud-mone...

[3] https://feedback.azure.com/forums/248703-api-management/sugg...

[4] https://aws.amazon.com/blogs/compute/monetize-your-apis-in-a...