Digi-Key vs Flipkart Marketplace

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.

Flipkart's Marketplace Seller API issues OAuth2 bearer tokens through either a client-credentials or an authorization-code grant, for self-access and third-party seller applications respectively. Its own documentation explicitly requires HTTPS and states plain HTTP requests are rejected, with tokens typically valid for around 60 days before they must be renewed.