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. Two read-only lookups work without a token: a category by ID, such as `/categories/MLA1051`, and `/sites/{site}/domain_discovery/search`. Everything else, including site lists, currencies, item listings and search, needs an OAuth2 access token from the authorization-code flow. The API itself carries no direct usage fee. Mercado Libre monetizes through marketplace and payment commissions instead.