The API marketplace is the recurring dream of this industry — an app store where providers list and consumers discover and buy. It has been attempted repeatedly for fifteen years with mixed and instructive results, because the app-store analogy turns out not to hold. APIs are not impulse purchases; they are dependencies that get evaluated, integrated, and depended on, and that process resists a storefront.
Where marketplaces reliably work is the cloud marketplaces, and the reason is procurement rather than discovery. A buyer with committed cloud spend and an approved vendor list can purchase through the marketplace without a new procurement cycle. That removes weeks from a deal. It is a channel into an existing budget, which is a much stronger proposition than “a place to be found.”
So list where your actual buyers already procure. Be realistic that a listing generates very little demand on its own — you still have to create the demand — and that the marketplace takes a cut and stands between you and the customer relationship.
And never let the listing substitute for your own developer experience. Consumers who find you through a marketplace will still land on your documentation, and that is where they decide.