Microservices API Gateway vs. Traditional API Gateway
The main aim of the microservices API gateway is to speed up the development of services independently. It provides the functionality for the team to publish, update and monitor the microservices independently and effectively. This functionality is not found in the traditional API gateway because it focuses on managing the APIs internally.
The industries and firms have worked on understanding this internal system thoroughly by defining the APIs. Therefore the challenge of revealing the thousands of APIs to the clients led to the exposure of API gateways. With passing time, the API gateway becomes the infrastructure center to access these APIs.
The below table shows a better representation of the difference between Microservices API Gateway vs. Traditional API Gateways.
Therefore, traditional API gateways solve the challenges that API management faces, but it fails to solve the difficulties adopted by microservices. Hence, the microservice API gateway integrated into your application allows service teams to monitor, update and publish the services safely and fast, enabling your organization to develop more software efficiently and effectively.
Working of an API Gateway in Microservices Architecture
Consider that you are building an eCommerce mobile application for clients where the application displays the product details. When making this application with a monolithic architecture, the client retrieves the data using a single REST call to the application. When we develop the same application with microservices architecture, each microservice reveals instructions for fine-grained endpoints.
Let’s make use of microservices architecture. The product details page displays the data by multiple microservices, for example, order services, shopping cart services, review services, shipping services, and much more.
Here, the client directly calls each microservices and distributes requests across the available instances. But when clients directly call the microservices, there are many issues faced, such as mismatch between the client call and APIs or use of protocols that are not web-friendly. API Gateway can solve this issue effectively. API gateway merges the internal system of the application and allows an API that each client adapts.
The below image explains how the API gateway manages the API calls and Interacts with other architecture components.
While implementing the API gateway in microservices architecture, scalability and performance of API Gateway are usually essential. The API Gateway is responsible for the functionalities including routing, billing, monitoring, rate limiting, authentication, adequate security, alerts, policies, etc. It helps to intercept incoming requests from clients and passes them to the API management system to apply necessary functions and get output. Various technologies are used to implement the scalability and performance of API gateway.
The API Gateway handles the request by routing them to the backend service. For example, the API gateway first retrieves the client’s profile containing the personal information before fetching the knowledge of the profile. It is best to write the API Gateway code rather than writing the API code using a traditional approach that is difficult to understand.
API gateway uses the system’s benefits, unlike any other service client, whether server-side discovery or client-side discovery. API Gateway always needs to know the IP address of each microservice to communicate. But deciding the application locations is not easy as application services have multiple locations assigned.
The most important thing to consider while using API gateway is the problem of partial failure of the system when one service calls another service that is responding slowly or is absent. However, there are solutions to this problem using API Gateway depending on the scenario and service failure.
Backend for Frontend (BFF) Pattern
In the backend for the frontend pattern, the backend service from the microservices architecture pattern serves as the endpoint for requesting the frontend.
We know that APIs are part of the applications functioning with one another with a single purpose. But over time of usage, there are chances of cracks or faults in the small piece of code, which helps everything stay aligned with one another. Therefore, the Backend for Frontend Pattern helps develop the backend niche for better user experiences individually. You can say that it is the layer between the frontend and the request backend calls.
Also, sometimes the output of data returned by the microservices to the front end is not in the exact format or the filter needed by the front end. To solve this issue, the frontend should have some logic to reformat the data, and therefore, we can use BFF to shift some of this logic to the intermediate layer. The primary function of the backend for frontend pattern is
- Get the required data by calling the appropriate microservice APIs
- Format the frontend data representation
- Send the formatted output to the frontend
Hence, BFF helps to reduce the logic handling responsibility of the frontend and enables a well-formatted interface to the frontend of the application.
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Read a complete guide to understand the Implementation of API Gateway — Issues and Solutions.