Digi-Key vs Mercadolibre

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.

Mercado Libre exposes a large REST surface across its Latin American marketplace sites, covering listings, orders, ads, and shipping. Public reference data like site categories is reachable without a token, but anything scoped to a seller account requires an OAuth2 access token obtained via an authorization-code or client-credentials grant. The API itself carries no direct usage fee — Mercado Libre monetizes through marketplace and payment commissions instead.