You Must use Amazon API.
Amazon API Link-https://www.amazon.com/ap/signin?openid.return_to=https%3A%2F%2Faffiliate-program.amazon.com%2Fassoc_credentials%2Fhome&openid.identity=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0%2Fidentifier_select&openid.assoc_handle=amzn_associates_us&openid.mode=checkid_setup&marketPlaceId=ATVPDKIKX0DER&openid.claimed_id=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0%2Fidentifier_select&openid.ns=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0&openid.pape.max_auth_age=0
Ebay API-https://developer.ebay.com/docs
Regards, Arnav Vashisth