Abstract: Provided herein are methodologies, systems, apparatus, and non-transitory computer-readable media for detecting firearm straw purchases and providing approval or denial of an attempted firearm purchase. Address information is collected from anyone attempting to purchase a firearm. This address information is normalized to create a normalized address string, which accounts for misspellings and/or abbreviations in the address information. This normalized address string is compared against normalized addresses associated with people who are prohibited from purchasing a firearm, and a similarity coefficient is calculated. The similarity coefficient is then compared against a threshold value, and if the similarity coefficient is greater than the threshold value, the firearm purchase can be declined. If, however, the similarity coefficient is below the threshold value, the firearm purchase can be approved.