Portico Developer Guide
Transaction Link Identifier
The Transaction Link Identifier (TLID) is a new unique transaction identifier generated by Mastercard to provide a more consistent method for linking related activity after the original authorization. The TLID is generated by Mastercard and returned in the first message of the transaction life-cycle and is included in all subsequent life-cycle messages.
For subsequent transactions in which an original transaction ID reference is provided (such as GatewayTxnId, Global Transaction Id, or Client Txn Id), Portico automatically associates the TLID from the original authorization on the merchant's behalf.
The TLID is returned in the transaction response in the TxnLinkId field.
In the future, Portico will allow the POS to send the TLID in a subsequent, financially-related transaction. This is only necessary when an original transaction ID reference cannot be provided.