API Gateways

An API gateway is the main element of the API architecture that simplifies the API integration and management of API requests. API gateways are situated between a client and backend services and help coordinate their communication. API gateways also centralize and ease API management and ensure compatibility of modern and legacy systems.

What Is an API Gateway?

An API gateway is located between a client and a set of backend services, which improves the integration between them. This is a tool that serves as the single entry point for the client. The client entering this point may be an application or device, e.g., a single-page application, a mobile application, an internal system, or a third-party service or system.

Two elements of the API gateway are control and data planes. Those elements can be bundled together or deployed independently. The control plane serves as an interface where administrators interact with gateways and determine routes, policies, and necessary data. The data plane is the setting where the incoming requests are handled according to the rules of the control plane. It routes network traffic, uses security policies, and generates logs or measures for tracking.

An API gateway applies policies for user authentication, request frequency limiting, and timeout/retry mechanisms. It also offers metrics, logs, and data to monitor performance, find troublesome issues, and analyze usage.

Why Use an API Gateway?

There are several key areas where API gateways become helpful.

An Adapter and a Facade: Enhancing System Flexibility

An API gateway provides an interface for engineers to interact with backend services. It should be flexible and understandable. All the parts of the system should be connected, but not heavily dependent on each other for the architects to be able to change some components without breaking the whole system. At the same time, the elements should serve a common goal. From the client’s perspective, they also use the API gateway as an interface to communicate with backend services. This way, an API gateway is like a facade that simplifies communication with the system. If the backend systems change, be it a location, architecture, or language, the API gateway adapts to those changes and clients do not feel the difference.

Orchestrating Backend Services

Sometimes it is necessary to gather the APIs of several backend services into a single client-facing API. It simplifies API consumption for frontend engineers, reduces the complexity of the backend, and improves request routing. A client may need to address several backend services. Doing this one by one is time-consuming. Orchestrating multiple calls to several independent backend APIs is faster and more convenient for a client. The results from backend services are gathered and transferred to a client in a single response.

Defending from Security Threats

An API gateway is the point of users’ first interaction with an API backend. Hackers can also be among those users. Huge enterprises typically have multiple security-focused measures such as web application firewalls (WAF), content delivery networks (CDN), dedicated demilitarised zones (DMZ), perimeter networks, etc. Smaller organizations also protect their API gateways with security-focused functionality. The following measures are cost-effective in dealing with unauthorized access, DDOS attacks, and excessive resource usage: authentication and authorization rules, monitoring and logging, HTTPS/TLS encryption, IP allow and deny lists, TLS termination, rate limiting, or load shedding for high-traffic scenarios.

Observing the API Consumption

Being at the edge of the system and receiving the majority of user requests, an API gateway provides important data about the application performance and customer satisfaction levels. The gateway enables monitoring of key performance indicators (KPIs) such as customer conversion rates, streaming initiation rates, revenue per hour, and detection of accidental or deliberate API abuse. It is a location to monitor the number of errors and throughput and to annotate requests that are transferred further through the system. All this data is important for further analysis and insights generation. The observability strategy usually implies dashboards and visualizations for correct interpretation of the metrics and alerting functionality for proactive issue resolution.

Managing API Lifecycle

Both internal and external parties use APIs. Large organizations develop an API strategy with goals, limitations, and resources set. A complete API lifecycle includes various stages, such as planning, designing, developing, testing, promoting, and others. Engineers and developers interact with API gateways during multiple of those stages. Besides, user traffic passes through the gateway. That is why implementing a relevant API gateway is critical.

Enabling Monetization

Often the APIs that are available to customers are developed as products. They are provided together with account management functionality and payment options. Modern enterprise API gateways allow for monetization. It is realized with such solutions as Apigee Edge and 3Scale. These portals integrate with PayPal or Stripe. Customers can set up rate limits, quotas, and consumption options to control the API usage.

Where Is an API Gateway Deployed?

For startups, small and medium-sized companies, an API gateway is usually located at the edge of the system. It might be the edge of the data center or cloud. In such a situation, a single API gateway guides users to the backend services.

For enterprises, an API gateway is situated in multiple locations, as it is a component of a product, line, business, or department. Therefore, the gateways become separate implementations and provide different functionality in accordance with requirements and possibilities, e.g., operating on devices with limited processing power.

Subtypes of API Gateways

There is no exact agreement about the classification of API gateways in the software development domain. Different industry segments demand different things and, consequently, there are different views about an API gateway. That is why several subtypes of API gateway may be discussed.

• Traditional Enterprise Gateways: Such API gateways are used to manage business-focused APIs. These gateways are integrated with API lifecycle management solutions and help to release, operate, and monetize APIs at scale. There are open-source solutions and commercial versions available on the market. However, they rely on additional services like databases. Those databases have to be reliable so as not to disrupt the gateway’s operations. Maintaining those dependencies adds expenses and should be taken into account in disaster recovery (DR) and business continuity (BC) plans.Q
• Microservices Gateways: They direct inbound traffic to backend APIs and services. They focus on tasks like routing, security, and traffic control and are not used for API’s lifecycle management. They are deployed as separate components and often use an underlying platform, e.g., Kubernetes, for scaling and maintenance.
• Service Mesh Gateways: This is a type of gateway that handles basic traffic management tasks. That is why they mostly lack enterprise features, such as integration with identity or authentication solutions.

Common API Gateway Pitfalls

There are some API gateway pitfalls that developers should try to avoid.

• Sometimes organizations need the service mesh functionality. They route the traffic through the API gateway. However, it may lead to performance and security troubles and demand additional expenses, as cloud vendors charge egress fees. Another problem is insufficient scalability which causes a gateway overloading.
• Many API gateways supplement their functionality by creating plugins and modules. Such features as logging or filtering are useful. However, if the whole business logic is put into plugins, it couples the gateway with services or applications. This may result in a fragile system, i.e., a change in the plugin impacts the whole organization. Besides, in such a situation, the release of the target service is deployed together with a plugin.
• Multiple API gateways are usually deployed in large organizations. It is done to segment departments or networks. It may become a problem though if there is a necessity to release a simple service upgrade. It requires the coordination of many gateway teams and the performance is negatively affected.

How Belitsoft Can Help

Software development companies like Belitsoft offer their services to technological startups and enterprises in developing, integrating, and testing API services gateways.

Identifying Requirements

Before developing any service, careful investigation of the client’s requirements and expectations takes place. We help clients achieve the following aims:

• Improve communication of the engineers with the backend
• Aggregate backend services to improve client consumption
• Secure APIs from overuse and abuse with threat detection and mitigation
• Monitor KPIs and throughput
• Implement API lifecycle management
• Monetize APIs, including account management, billing, and payment

Providing the roadmap with team augmentation and technological support

At Belitsoft, we develop a roadmap tailored to the client’s demands. We take into account organizational structure to make sure all future decisions regarding the API gateway maintenance will be taken without constraints. We also analyze existing technologies in order to make them fit new API gateways.

• Our API developers specialize in Java Spring Boot, Python FastAPI, and .NET Core
• We implement and configure API Gateways to centralize and simplify API management, enable rate-limiting authentication, caching, data transformation, and abuse protection
• Belitsoft provides expertise in deploying and configuring AWS and Azure API gateways

If you are looking for specialized API expertise, improved API quality, and a scalable API team, the Belitsoft software development company offers outsourced services to meet your needs. Contact us today to discuss your project requirements.