When applications use a microservices architecture, it's possible for clients and microservices to communicate directly. However, this operation is suitable for a restricted functional domain where you have a small number of microservices. The greater the number of microservices available, the more complicated it will be to know which microservice should be called. All the more so since a client will often have to call several microservices to collect all the data necessary for the operation of the application.
To optimize the application, you'll need to ask several questions, limit the number of requests sent to the back end, and manage problems such as security. You can use an API gateway to do this.
In this post, we'll explain how you can use API gateways to improve security.
What Is an API Gateway?
An API gateway acts as a single entry point for the client (web application, mobile application, etc.) and protects the back-end APIs by monitoring and securing traffic and ensuring the availability of services.
It can do several things, including the following:
Aggregate or disaggregate different APIs
Realize the transformation of protocols or data, the use of non-internet compatible protocols, and the caching and orchestration of different APIs
Centralize security, thus avoiding having to do it at the level of the APIs of the application server
Participate in the availability and scalability of the application
Contribute to the simplicity of API consumption by consumers
Why Use an API Gateway Instead of Direct Client-to-API Communication?
The greater the number of APIs available, the more complicated it is to know which API should be called. This is all the more so since a client often calls several APIs to collect the data necessary for the operation of the application.
Without an API gateway, client applications send requests directly to APIs with the following implications:
Applications must precisely know all the services to call them.
Network latency may increase by forcing multiple round trips between the client application and the back end.
Ensuring data security is also more complicated since all services are exposed publicly, thus increasing the attack surface.
In addition, as the API gateway abstracts from the actual implementation of the service or services, it may present consumers with only the necessary information and manage API versioning more simply.
How Is an API Gateway Different from an API Manager?
There are some differences between an API manager and an API gateway. To begin with, in terms of functionality, an API manager has a much larger number of functions than an API gateway, which is more restricted to API security and targeting filters.
In practice, an API manager incorporates an API gateway in its structure, acting as if it were a management system. The tool comprises features that facilitate the development and application of other APIs. These help reinforce usage rules, improve access control, collect and analyze usage statistics in detail, and manage the entire API lifecycle.
How API Gateways Help with Security
A successful cyberattack can expose company, application, and user data. With that in mind, API gateways increase the system's security, protecting it from attacks by malicious agents.
It is possible to add a protective layer that fights vectors triggered by digital attacks using a buffer zone. This turns the application's focus to the business while the cache and security are in charge of the API gateway.
API gateways provide a single access point for the exchange of flows, controlling calls between third-party systems and the traffic of data. In addition, they offer greater control over shared information through the centralization of everything in one interface.
With an API gateway, it's possible, for example, to limit the permission of an accounting partner so that they can only view financial information, blocking the view of patient data. As a result, the organization can be sure the data is safe, and so can users. At the same time, tech teams do not need to exert as much effort. Instead, they can rely on a single place to manage integrations between numerous systems. That means more data security and less work.
An API gateway does not only coordinate and control services that are immune to attacks. It also guarantees that the system as a whole will not get affected if there's a vulnerability. Thus, in addition to reducing damage in case of attacks, this strategy helps users, since the other features remain normal during an attack.
Using an API gateway simplifies your architecture, makes it more secure, and reduces the network load since it ignores the actual implementation of the microservice or microservices. By disregarding the actual implementation of the microservices or even by calling old applications in monolithic type architectures, for example, it can standardize the return message while allowing calls to different types of services: API, SOAP, and REST among others.
API Gateway Security Best Practices
An API gateway must be independent and sit between the client and the back end. As the microservices abstraction layer, it acts as a reverse proxy by redistributing requests to various corresponding microservices. It therefore becomes an entry point to the application. In this layer, it's possible to implement additional functionalities such as authentication, cache, or security (SSL, for example).
The API gateway must also be replicated and load balanced to avoid becoming the "single point of failure" application. Thus, it must not become monolithic and group all calls to microservices. You can separate API gateways using functional domains or platforms (desktop, web, mobile). It will balance the load and give the correct data to provide to the client.
You can delegate authentication or cache implementations to the gateway, thereby avoiding specific implementations for each microservice. It improves implementation times by reducing the load, makes it easier to write and read microservices code by outsourcing certain portions, and facilitates scalability. This is because these implementations are "centralized" and therefore easier to scale, and microservices that refrain from these implementations are easier to maintain and scale.
An API gateway, if implemented correctly, yields many benefits. There are still risks, such as becoming a centralized point of failure. The API gateway may become a bottleneck. However, solutions such as AWS API Gateway, Azure API Management for Azure, or Ocelot for .Net Core. are available to solve these kinds of problems.
This post was written by Talha Khalid. Talha is a full-stack developer and data scientist who loves to make the cold and hard topics exciting and easy to understand.