An application firewall is a security system designed to monitor and control incoming and outgoing network traffic specifically for applications. Unlike traditional firewalls that protect entire networks, application firewalls focus on individual applications, filtering data based on predefined security rules. This helps prevent unauthorized access and attacks, such as SQL injection or cross-site scripting. These firewalls can be implemented as software or hardware solutions and are often used in conjunction with other security measures. By analyzing the data packets at the application layer, they provide a more granular level of protection, ensuring that only legitimate traffic reaches the application and safeguarding sensitive information.