How this list works
The table below is derived from the live catalog: a model provider is listed while it has a published endpoint, with the data policy its endpoints declare (zero retention, retention, training) and how many endpoints carry no verified declaration yet; the upstream routing provider is listed while it forwards traffic for a published endpoint, because it receives request content in transit; the payment processor is listed for card payments; and the identity verification provider is listed while identity verification is in use, because it checks identity documents for the accounts asked to verify. Your routing policy decides which of these providers may receive your traffic. Hosting and support-tooling vendors are not listed because no vendor register exists yet; the page says so rather than naming any.