Best Buy vs OLX Poland

Best Buy's public REST API exposes product, store, category, and recommendation data behind a free API key registered through its developer portal. Responses can be returned as either JSON or XML for most endpoints, though the newer Recommendations endpoints are JSON-only. Live probing shows the gateway actively validates keys server-side but returns no CORS headers, so it is built for server-side integration rather than direct browser calls.

OLX Poland's Partner API lets approved integrators create and manage classified-ad listings and handle buyer/seller messaging programmatically. Access runs on an OAuth2 client-credentials flow, confirmed live by an invalid_client error from the real token endpoint, and the older v1 REST resource has been explicitly deprecated in favor of this OAuth-secured surface. Developer access comes through an application and approval process rather than a published self-serve fee.