Abstract: The likelihood of a successful transaction may vary according to associated variables (e.g., time of day, day of week or month, proxy or API used, etc.) and/or depending on the transaction route that is used. Accordingly, success rates may be generated for transaction routes using associated variables, which may be used to update rules relating to transaction routing. In addition, fault-tolerant routing may be used to ensure that a transaction ultimately succeeds even if a first or even a second transaction attempt fails. Rules may be used to ensure that customer guarantees are satisfied (e.g., that the transaction is completed on time or by a specified due date), that additional information is requested from the customer as needed (e.g., as may be required by an alternative payment method), and that the customer remains apprised of the status of his or her payments.