Digi-Key vs OLX Poland

Digi-Key's api.digikey.com gateway runs a genuine OAuth2 flow: its authorization endpoint rejects requests missing a client_id, and resource endpoints additionally require a client-specific header, ruling out simple API-key auth. Access to product, ordering, and barcode data is free with per-product rate limits, and CORS is explicitly configured, echoing the request Origin on both live calls and OPTIONS preflights.

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.