Transaction Flow

While many transactions follow a basic flow consisting of an initial authorization and a subsequent clearing message to settle funds, at times more complicated lifecycles occur.

Network transmits ISO-8583 MTI 0100 message to Lithic.
Lithic converts the ISO-8583 message to transaction model JSON and sends an ASA request to the client.
The client responds with HTTP 200 ASA JSON response body with result APPROVED.
Lithic converts the ASA response body to ISO-8583 response and returns to the network.
Acquirer initiates completion of the transactions and Lithic receives ISO-8583 MTI 0220 advice from the network.
Lithic processes the ISO-8583 message and responds with an approved response back to the network.
Lithic converts the ISO-8583 message to a JSON transaction model with status SETTLED and sends a Clearing message to the client. Step 6 & 7 are processed concurrently.
The client responds with HTTP response code 200 to acknowledge.

Transaction Sequence


Sequence	Description	Indicator
Authorization Reversal	Acquirer initiates reversal of pending authorization. Authorization expires after 7 days or after the authorization lifecycle, whichever comes last	The transaction model in step 7 contains status `VOIDED`. The most recent event contains event type `VOID`
Authorization Timeout	Issuer has exceeded the authorization maximum response time and the network has issued a decline to the acquirer on behalf of the issuer	The transaction model in step 7 contains status `VOIDED`. The most recent event contains event type `AUTH_ADVICE`
Force Post	The acquirer may initiate a forced clearing transaction with no prior authorization. These transactions are subject to chargeback upon cardholder dispute	Steps 1-4 are omitted. Transaction model in step 7 contains status `SETTLED`
Financial Authorization	A single-message (SMS) transaction. The effective date is immediate upon approval. No additional clearing message will be sent	`FINANCIAL_AUTHORIZATION` status indicates SMS flow. Steps 5-8 are omitted
Financial Authorization Reversal	A financial authorization may be reversed. This is similar to a refund except that the financial reversal will be associated with the original authorization (refunds are always separate transactions)	`FINANCIAL_AUTHORIZATION` webhook will contain status `SETTLED`. Upon financial reversal, the new status of the transaction will be `VOIDED`
Multiple Completion	Multiple permutations of partial completion and partial reversal may follow an approved authorization	Advice messages replacing step 7 with type `CLEARING` or `VOID` with respective amount and settled_amount indicators
Authorization Advice	Advice may adjust the authorization to a higher or lower amount	Advice message between steps 2 and 7 with event type `AUTH_ADVICE` including the new amount. The total of subsequent `CLEARING` event transactions will be for the amount indicated in the advice message