Ensuring data security in a mobile app involves several key practices top companies such as mobile app development services in delaware usually follow these steps. First, implement strong encryption for data both at rest and in transit to protect sensitive information. Use secure authentication methods, such as multi-factor authentication, to prevent unauthorized access. Regularly update and patch the app to fix vulnerabilities and conduct thorough security testing to identify potential risks. Implement secure coding practices to avoid common vulnerabilities like SQL injection and cross-site scripting.