As businesses move toward cloud-native and microservices architectures, one question comes up again and again: What is an API gateway? And why has it become such a critical component of modern applications?
From powering scalable platforms to enabling ecommerce store analytics, integrations, and headless experiences, API gateways now sit at the heart of digital systems. In this guide, we’ll explain the meaning, architecture, key features and real-world microservices use cases of an API Gateway.
What Is an API Gateway?
An API Gateway is a server that acts as a single entry point for all client requests to backend services. Instead of clients calling multiple microservices directly, they send requests to the API gateway, which then routes them to the appropriate service.
So when people ask what is api gateway or what is an api gateway, the simplest answer is:
It’s the front door to your APIs.
In modern systems, especially api gateway microservices architectures, it also handles security, traffic management and transformations - making APIs easier to consume and safer to expose.
Why Is an API Gateway Used in Microservices?
In microservices, applications are split into dozens (or hundreds) of small services. Without a gateway, clients would need to:
Know every service endpoint
Handle authentication for each service
Manage retries, failures and versions
This quickly becomes complex.
That’s why what is api gateway in microservices is such a common search. An API Gateway is used because it:
Simplifies client interactions
Centralises authentication and security
Hides internal service structure
Improves performance via aggregation & caching
Provides observability and control
Platforms like Commerce Engine use API gateways to expose commerce APIs for storefronts, partners and integrations while keeping internal services decoupled.
How Does an API Gateway Work in a Microservices Architecture?
To understand api gateway architecture, here’s a typical flow:
Client → API Gateway → Microservices → API Gateway → Client
The API gateway:
Receives the request
Authenticates and authorises the client
Applies rate limits or policies
Routes the request to one or more services
Aggregates responses if needed
Sends a single response back to the client
In commerce platforms, this allows seamless integrations for checkout, catalogues, best payment gateway providers and shipping and carrier integration for 3PL, all through one unified API layer.
API Gateway Architecture Explained
A standard api gateway architecture includes:
Edge layer – Entry point handling traffic
Routing layer – Directs requests to services
Policy engine – Auth, rate limiting, quotas
Transformation layer – Protocol & payload changes
Observability – Logs, metrics, tracing
Developer portal – Docs, keys, onboarding
In API-first platforms like Commerce Engine, this architecture enables flexible integrations with order management solutions and analytics systems without exposing internal complexity.
Key Features of an API Gateway
If you’re evaluating api gateways, these are the essential features to look for:
Authentication & authorization
Rate limiting & throttling
Request/response transformation
Service routing & discovery
API aggregation
Version management
Monitoring & logging
Developer portal & API keys
Caching & performance optimization
These features make the API gateway much more than just a router - it becomes a control plane for your entire API ecosystem.
What Problems Does an API Gateway Solve?
An API Gateway addresses several challenges in modern applications:
Too many endpoints – Hides microservice sprawl
Security gaps – Centralises auth and policies
Client complexity – Offers a single API surface
Performance issues – Aggregates and caches responses
Lack of visibility – Provides unified monitoring
Version chaos – Manages API evolution
This is especially important in large systems handling payments, fulfilment and e-commerce store analytics, where consistency and reliability are critical.
API Gateway vs Load Balancer: What’s the Difference?
A frequent question is: What is the difference between an API Gateway and a load balancer?
In short:
A load balancer spreads traffic.
An API Gateway governs APIs.
Both can coexist, but they solve different problems.
Common Use Cases of an API Gateway in Microservices
Here are typical api gateway microservices use cases:
Single entry point for all clients
Central security layer
API aggregation across services
Protocol translation (REST, GraphQL, gRPC)
Partner & third-party integrations
Headless commerce APIs for storefronts
Integrating the best payment gateway providers
Enabling shipping and carrier integration for 3PL
Syncing with order management solutions
In Commerce Engine, these use cases power flexible B2B and D2C commerce experiences across web, mobile and partner channels.
Popular API Gateway Tools and Platforms
Some widely used API Gateway solutions include:
AWS API Gateway
Azure API Management
Google Apigee
Kong
NGINX
Tyk
Envoy Gateway
The right choice depends on scale, cloud strategy and how deeply APIs are embedded in your product.
FAQs About API Gateways
What is an API Gateway and why is it used in microservices?
An API Gateway is a single entry point for APIs that simplifies client access, centralises security and manages traffic in microservices architectures.
How does an API Gateway work in microservices?
It receives requests, applies policies, routes them to services, aggregates responses and returns a unified response to the client.
What are the key features of an API Gateway?
Authentication, rate limiting, routing, transformations, aggregation, versioning, monitoring and developer portals.
What problems does an API Gateway solve?
It reduces complexity, improves security, enhances performance and provides visibility across distributed services.
What is the difference between an API Gateway and a load balancer?
A load balancer distributes traffic, while an API Gateway manages and governs APIs with policies and lifecycle features.
What are common API Gateway use cases in microservices?
Single entry point, API aggregation, security, partner integrations, headless commerce APIs, payments, shipping and OMS integrations.
Which are the most popular API Gateway tools and platforms?
AWS API Gateway, Apigee, Kong, NGINX, Azure API Management and Tyk are among the most popular.
Final Thoughts
Now that you know what is an API Gateway, its architecture and how it powers microservices, it’s clear why it has become a foundation for modern digital platforms.
For API-first systems like Commerce Engine, the API gateway enables secure, scalable integrations for storefronts, analytics, payments, shipping and order management, all while keeping the platform flexible and future-ready.
If you’re building microservices or a headless commerce stack, investing in the right API gateway strategy can dramatically improve reliability, performance and developer experience.
