Usage of API gateway

Usage of API gateway

In this tutorial, we are going to discuss about usage of API gateway in system design. API Gateways play a crucial role in system design across various domains and architectures.

Usage of API gateway

API Gateway technology offers a range of benefits such as efficient management of incoming requests that easily routes them to pertinent backend services. Moreover, it can automatically translate protocols so that clients can interact with the service effortlessly. API gateways are used for a variety of purposes in microservice architectures, including the following

1. Routing

The API gateway receives requests from clients and routes them to the appropriate microservice. This enables clients to access the various microservices through a single entry point, simplifying the overall system design.

API gateways act as intermediaries between clients and backend services, providing a centralized entry point for accessing distributed resources.

2. Rate limiting and throttling

Rate limiting and throttling are essential features provided by API gateways to manage the rate of incoming requests from clients, prevent abuse, and ensure fair usage of backend resources. This can help prevent denial of service attacks and other types of malicious behavior.

Rate Limiting:

  • Rate limiting restricts the number of requests that clients can make to an API within a specified time period. This prevents clients from overwhelming the backend services with a high volume of requests and helps ensure the stability and availability of the system.
  • Rate limiting can be applied globally to all clients accessing the API or on a per-client basis, depending on the level of granularity required.
  • The API gateway tracks the number of requests made by each client and enforces rate limits by rejecting or delaying requests that exceed the defined thresholds.
  • Rate limits can be configured based on various criteria such as IP address, API key, user identity, or client type.


  • Throttling limits the rate at which requests are forwarded from the API gateway to the backend services. This helps prevent backend services from being overwhelmed by a sudden influx of requests and ensures that they can handle incoming traffic efficiently.
  • Throttling can be applied globally to all requests or on a per-backend-service basis, depending on the specific requirements and constraints of the system.
  • The API gateway regulates the rate at which requests are forwarded to backend services, typically by introducing delays or queuing requests when the rate exceeds predefined thresholds.
  • Throttling mechanisms may employ techniques such as token bucket algorithms, leaky bucket algorithms, or sliding window counters to control the rate of request forwarding effectively.
3. Caching

Caching in an API gateway involves storing responses from backend services temporarily and serving them directly to clients without forwarding the requests to the backend again. This can significantly improve the performance, reduce latency, and alleviate load on backend servers.

When a client sends a request to the API gateway, the gateway checks if there is a cached response for that request in its cache storage.

If a cached response exists and is still valid (i.e., it has not expired), the API gateway returns the cached response directly to the client without forwarding the request to the backend service.

4. Authentication and Authorization

Authentication and authorization in an API gateway are crucial for ensuring that only authorized users or clients can access protected resources and perform permitted actions. API gateways typically provide mechanisms for implementing authentication and authorization policies to enforce security requirements.

This helps to ensure that only authorized clients can access the microservices and helps to prevent unauthorized access.

By implementing robust authentication and authorization mechanisms in the API gateway, organizations can protect their APIs and backend services from unauthorized access, data breaches, and other security threats. These security measures ensure that sensitive information remains confidential, integrity is maintained, and resources are accessed only by authorized users or clients.

5. Load balancing

Load balancing in an API gateway involves distributing incoming client requests across multiple backend servers or services to ensure optimal resource utilization, scalability, and reliability. API gateways typically offer load balancing features to handle high volumes of incoming traffic and distribute requests evenly across backend instances.

By implementing load balancing in the API gateway, organizations can achieve improved scalability, availability, and performance for their APIs and backend services. Load balancing ensures that incoming requests are distributed efficiently across backend instances, maximizing resource utilization and minimizing response times for clients.

6. Monitoring

Monitoring in an API gateway involves tracking and analyzing various metrics, logs, and events to ensure the health, performance, and security of the API gateway and the services it proxies. Effective monitoring allows operators to detect issues, troubleshoot problems, optimize performance, and ensure compliance with service level agreements (SLAs). This can help to identify and diagnose problems, and improve the overall reliability and resilience of the system.

By implementing comprehensive monitoring capabilities in the API gateway, organizations can proactively manage and optimize the performance, security, and compliance of their APIs and backend services. Monitoring enables operators to detect issues early, respond quickly to incidents, and continuously improve the reliability and efficiency of the API gateway infrastructure.

7. Transformation

The API gateway can be used to transform the data received from the microservices into a format that is more convenient for the clients to use. This can include tasks such as converting between different data formats, such as XML and JSON, or aggregating data from multiple microservices into a single response.

8. Service discovery

The API gateway can be used to discover the available microservices and their locations, enabling the clients to access them without knowing their specific addresses. This can make it easier to add new microservices or make changes to the existing ones without impacting the clients.

Service discovery in an API gateway involves dynamically identifying and locating backend services or microservices that provide the functionality exposed through the gateway’s APIs. Service discovery enables the API gateway to route incoming requests to the appropriate backend services based on the requested endpoints, without requiring manual configuration or hardcoding of service endpoints.

By leveraging service discovery in the API gateway, organizations can build highly resilient, scalable, and adaptable API infrastructures that seamlessly integrate with dynamic microservices architectures. Service discovery simplifies the management of backend service interactions, promotes flexibility and agility, and enhances the reliability and performance of API-driven applications.

9. Circuit breaker

The API gateway can be used to implement a circuit breaker pattern, which can help to 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.

By incorporating circuit breakers in the API gateway, organizations can improve the reliability, availability, and performance of their APIs and backend services. Circuit breakers help isolate failures, prevent service overload, and maintain service quality under adverse conditions, ensuring a consistent and responsive user experience for API consumers.

10. Request and response validation

Request and response validation in an API gateway involves inspecting incoming requests and outgoing responses to ensure they adhere to predefined standards, constraints, and security policies. Validating requests and responses helps maintain data integrity, security, and compliance with API specifications. This can help to prevent errors and ensure that the microservices are functioning properly.

By implementing robust request and response validation mechanisms in the API gateway, organizations can enhance the security, reliability, and compliance of their APIs, mitigate risks associated with invalid or malicious data, and provide a consistent and trustworthy experience for API consumers. Effective validation ensures that APIs behave predictably, handle inputs safely, and protect sensitive information from unauthorized access or manipulation.

11. Error Handling

Error handling in an API gateway is crucial for providing a reliable and user-friendly experience to clients interacting with the APIs. Effective error handling ensures that clients receive meaningful error responses and guidance on how to resolve issues encountered during API usage.

By implementing robust error handling mechanisms in the API gateway, organizations can enhance the reliability, resilience, and usability of their APIs, minimize service disruptions, and improve the overall developer and user experience. Effective error handling fosters trust and confidence in the API ecosystem, enabling clients to interact with APIs confidently and efficiently.

12. API Versioning

API versioning in an API gateway is a critical aspect of managing changes to APIs over time while ensuring backward compatibility and providing a consistent experience for clients. Versioning allows organizations to introduce new features, modify existing functionality, and deprecate outdated endpoints without disrupting existing integrations.

By implementing robust versioning mechanisms in the API gateway, organizations can effectively manage changes to APIs, accommodate evolving business needs, and maintain compatibility with existing client applications. Versioning promotes interoperability, facilitates API evolution, and fosters collaboration between API providers and consumers.

13. Service Aggregation

Service aggregation in an API gateway involves combining multiple backend services or microservices into a unified API interface, providing clients with access to aggregated data and functionalities through a single entry point. This approach simplifies client interactions, improves performance, and enhances the user experience by abstracting away the complexity of interacting with multiple underlying services.

By leveraging service aggregation in the API gateway, organizations can streamline client interactions, consolidate disparate services, and provide unified access to distributed data and functionality. Service aggregation simplifies integration efforts for clients, improves performance and scalability, and enhances the overall agility and competitiveness of the API ecosystem.

14. Web Application Firewall (WAF)

A Web Application Firewall (WAF) in an API gateway serves as a critical security component, protecting web applications and APIs from a wide range of attacks, including injection attacks, cross-site scripting (XSS), cross-site request forgery (CSRF), and other common web vulnerabilities.

By deploying a WAF within the API gateway, organizations can strengthen the security posture of their web applications and APIs, mitigate the risk of data breaches and cyber attacks, and ensure compliance with industry regulations and security best practices.

15. API Documentation

API documentation in an API gateway is a critical component for developers who need to understand how to interact with the APIs exposed through the gateway. Good documentation provides comprehensive guidance on the available endpoints, request and response formats, authentication mechanisms, error handling, and other important details.

Well-documented APIs increase developer satisfaction, foster innovation, and drive adoption of APIs within the developer community.

That’s all about usage of API gateway in system design. Overall, API gateways serve as a critical component in system architecture, providing a unified interface for clients to interact with backend services while offering various features to improve security, scalability, reliability, and developer experience.

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Usage of API gateway
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