> For the complete documentation index, see [llms.txt](https://hanfak.gitbook.io/workspace/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hanfak.gitbook.io/workspace/general-paradigms/patterns/api-gateway.md). # Api gateway * An API gateway is a server that acts as a single point of entry for a set of microservices. ## Usages * Routing * Authentication and Authorization * authenticate clients and enforce access control policies for the microservices * Rate limiting * Load balancing * Caching * Monitoring * collect metrics and other data about requests and responses * Transformation * transform the data received from the microservices into a format that is more convenient for the clients or servers to use * To different formats, or aggregating data for clietns * Request and response validation * Service discovery * discover the available microservices and their locations, enabling the clients to access them without knowing their specific addresses * Circuit breaker * prevent a single failed microservice from bringing down the entire system. The circuit breaker can monitor the health of the microservices and automatically fail over to a backup service if necessary. ## Advantages * Improved performance * enabling it to handle a larger number of requests and respond more quickly to the clients. * Simplified system design * makes it easier for the clients to access the various microservices. * Enhanced security * Improved scalability * By load balancing * Better monitoring and visibility ## Disadvantages * Increased complexity * increase managing and maintainability * Performance overhead * another request * Single point of failure * Can be mitagated by using a hot standby * *