Most services require an Access Token. To get one, you first need to get your seller's account credentials.
To do it, go to https://www.mercadopago.com/:siteId/account/credentials?type=basic
(where :siteId is your account’s country id) and log in. You can now access your client_id and client_secret.
mla - Argentina
mlb - Brazil
mlv - Venezuela
mlc - Chile
mlm - Mexico
mco - Colombia
mlu - Uruguay
Example (Uruguay): https://www.mercadopago.com/mlu/account/credentials?type=basic
Once you get your credentials, you must setup the SDK to use them. In the SDK in GeneXus, find the “GetCredentials” procedure and set &Client_id and &Client_secret with your credentials.
To get your token, call the procedure GetAccessToken(), which returns an AccessTokenSDT with the token's information. Keep in mind this token is valid for 6 hours, after which it must be renewed.
Note: In Sample, there is a procedure (GetCurrentToken()) that calls ObtainAccessToken(), which renews the Access Token automatically if necessary, every time it's needed, saves it in your local BD and returns a valid token.