An API gateway is a device or software that acts as an intermediary between clients and servers that provide web services through application programming interfaces (APIs). An API gateway can provide various functions such as:
* Terminating SSL connections at a central location, reducing the overhead on the backend servers and simplifying certificate management
* Managing both authentication and authorization for incoming and outgoing web service calls, enforcing security policies and access control
* Advertising the web service API, providing documentation and discovery features for developers and consumers
* Implementing DLP and anti-malware features, preventing data leakage and malicious code injection A web application firewall (WAF) is a device or software that filters and blocks malicious web traffic from reaching an application. A WAF can provide some protection for web services, but it does not provide all the functions of an API gateway. An XML gateway is a device or software that validates, transforms, and routes XML messages between clients and servers that provide web services. An XML gateway can provide some functions of an API gateway, but it is limited to XML-based web services and does not support other formats such as JSON. An enterprise service bus (ESB) gateway is a device or software that integrates and orchestrates multiple web services into a single service or application. An ESB gateway can provide some functions of an API gateway, but it is more focused on business logic and workflow rather than security and performance. References: [CompTIA Advanced Security Practitioner (CASP+) Certification Exam Objectives], Domain 2: Enterprise Security Architecture, Objective 2.3:
Implement solutions for the secure use of cloud services