In sum, the answer to Do APIs cost money? is a resounding yes, at least when the APIs offer significant value to businesses. It's a strategic decision by companies to monetize their data, with charges often directly proportional to usage. Are you interested in integrating an API into your business plan?
For HTTP APIs and REST APIs, you pay only for the API calls you receive and the amount of data transferred out. There are no data transfer out charges for Private APIs. However, AWS PrivateLink charges apply when using Private APIs in API Gateway.