CorrLinks is a great app developed in partnership with ATG and a corrections agency, providing messaging services to users whose friends and relatives are in prison. It features real-time push notifications and a 60-day message retention. All messages are automatically downloaded to your device, ensuring ease of access. You can bind multiple devices to your CorrLinks accounts so you can speak to your incarcerated friend or family member anytime you want. 

CorrLinks is currently allowed in Iowa, Wisconsin, Massachusetts, Nevada, and Oklahoma's Federal Bureau of Prisons and Department of Corrections (DOC). Before downloading this tool, make sure that you own a Premier Account, which sets you back at an annual rate of $6.0.