1. A method comprising: associating, by a reward card engine of a computer based system, a registration identifier with a transaction account, wherein the transaction account is associated with a rewards program based on transaction account identifying information and the transaction account satisfying eligibility criteria, and wherein the registration identifier indicates that the transaction account is associated with the rewards program; creating, by an offer registration system of the computer based system, active offers in response to receiving offer parameters and merchant information from one or more merchants, wherein the active offers and the offer parameters are stored in an offer database; associating, by the offer registration system of the computer based system, the active offers with the transaction account, wherein the active offers are associated with the transaction account based on the offer parameters; receiving, by the computer based system, transaction information for a transaction at the merchant; determining, by the computer based system, that the transaction information is associated with the registration identifier; determining, by the computer based system, that the transaction is associated with the transaction account and the rewards program based on the registration identifier and the transaction information; authorizing, by the computer based system, the transaction with the merchant, wherein the authorization is based on an amount of available credit associated with the transaction account; reducing, by the computer based system, the amount of available credit for the transaction account by a transaction amount included with the authorization; receiving, by the computer based system, the transaction information for the transaction from the merchant as part of a settlement operation for the transaction between the merchant and a transaction account issuer; determining, by the computer based system, the merchant from which the transaction was initiated; generating, by the computer based system and in response to the settlement operation, a list of the one or more merchants with the active offers which is a subset of the active offers from the one or more merchants; analyzing, by the computer based system, the merchant against the list of the one or more merchants with the active offers; analyzing, by the computer based system, the transaction information to determine that the transaction satisfies the offer parameters for an offer, wherein the offer is one of the active offers; selecting, by the computer based system and in response to the satisfying, the offer; linking, by the computer based system and in response to the selecting, the offer with the registration identifier; associating, by the computer based system and in response to the linking with the registration identifier, the offer with the transaction account based on the registration identifier; determining, by the computer based system, an amount of a reward based on the offer parameters; and crediting, by the computer based system, the amount of the reward to the transaction account in response to the transaction information satisfying transaction criteria.