The author of this text is a member of Sainsbury's team responsible for ensuring service stability and customer experience through site reliability engineering (SRE). They developed an app called Twitter Alerts to track social media signals, such as tweets mentioning issues with the company's services, and correlate them with systems that may be alerting. This allows the team to quickly identify problems and resolve them before they impact customers. The app uses a simple Python script to stream data from Twitter, pattern match it to certain keywords, and then fire it into New Relic as event data. The author also customized the visualization of the data in the app, including using responsive design for mobile viewing, and established alert policies on issues identified by customers through Twitter. The Twitter Alerts app has provided immediate visibility into customer experience and has helped the team to identify and resolve issues quickly, giving them confidence that customers are not having any issues.