# What Is an API Gateway? Definition and Examples > An API gateway is a single entry point that sits in front of your backend services and routes each API request to the right one, while handling authentication, rate limiting and logging. - **Term:** API gateway - **Part of speech:** noun - **Pronunciation:** /ˌeɪ piː aɪ ˈɡeɪtweɪ/ - **English level (CEFR):** C1 - **Register:** Neutral, Both - **Region:** US and UK - **Topic:** [Tech jargon](https://app.speaktechenglish.com/learn/topics/tech-jargon.md) - **Lesson:** https://app.speaktechenglish.com/learn/api-gateway - **Last updated:** 2026-10-27 ## Meaning An API gateway is a single entry point that sits in front of your backend services and routes each API request to the right one, while handling authentication, rate limiting and logging. An API gateway is a single entry point that sits between clients (apps, browsers, partners) and your backend services. Instead of calling ten services directly, a client calls the gateway, and the gateway sends each request to the right service. The gateway also handles shared jobs in one place: authentication, rate limiting, routing, caching, logging and sometimes changing the format of requests or responses. In a microservices system, this keeps each service simpler. A gateway can become a bottleneck or a single point of failure, so teams run several copies and monitor it closely. It is not the same as a load balancer, which only spreads traffic, or a reverse proxy, which forwards requests. A gateway adds API features on top. Common examples are Kong, Apigee and Amazon API Gateway. ## When you hear it We deployed an API gateway to centralize authentication and rate limiting across all our microservices. ## Examples - **in a design review:** "All mobile traffic goes through the API gateway, which handles auth and rate limiting." - **in an incident call:** "Requests are timing out at the gateway, but the backend services look healthy." - **in an architecture discussion:** "We should not add business logic to the gateway. It should only route and protect." - **in a planning meeting:** "Moving token validation to the API gateway will remove duplicate code from five services." ## What native speakers say - "The API gateway routes requests to the appropriate backend service" - "We implemented rate limiting at the API gateway level" - "All external traffic flows through the API gateway" ## Common mistakes - ✗ "We use the API gateway to store user data." → ✓ "We use the API gateway to authenticate users and route requests to the backend service that stores user data." (An API gateway manages request flow and policies, not data storage. It is a routing and management layer.) - ✗ "The API gateway is the same as a load balancer." → ✓ "The API gateway includes load balancing capabilities, but also handles authentication, rate limiting, and request transformation." (While both manage traffic, an API gateway has broader responsibilities for API-specific management tasks.) - ✗ "We need to bypass the API gateway for performance reasons." → ✓ "We optimized the API gateway configuration to reduce latency while maintaining security policies." (Bypassing the gateway compromises security and management. Instead, optimize the gateway itself.) ## Be careful Often confused with load balancer or reverse proxy; an API gateway is specifically designed to manage API requests and applies business logic like authentication and rate limiting. ## Word forms | Part of speech | Word | Example | | --- | --- | --- | | noun | API gateway | The API gateway manages all incoming requests. | | noun | API gateways | We operate multiple API gateways for redundancy. | | adjective | API gateway configuration | The API gateway configuration needs to be updated. | ## Collocations - **deploy an API gateway**: Used when setting up or releasing an API gateway into production - **API gateway layer**: Refers to the architectural layer where the API gateway operates - **API gateway routing**: The process of directing requests to appropriate backend services - **API gateway authentication**: Security mechanism implemented at the gateway level - **API gateway rate limiting**: Controlling request frequency to prevent overload - **API gateway latency**: Delay introduced by the gateway in request processing ## Synonyms - **API server**: Less specific; refers to any server managing APIs, not necessarily a dedicated gateway component - **service mesh ingress**: Similar concept in Kubernetes environments; focuses on service-to-service communication - **reverse proxy**: More general term; an API gateway is a specialized type of reverse proxy with API-specific features ## Opposites - direct client-to-service communication - monolithic architecture ## Practice This lesson has 4 practice exercises with instant feedback on the page: https://app.speaktechenglish.com/learn/api-gateway ## FAQ ### Why use an API gateway? Clients call one address instead of many services. The gateway handles shared jobs like checking tokens, limiting traffic and collecting metrics, so each service does not repeat them. ### What is the difference between an API gateway and a load balancer? A load balancer spreads traffic across copies of the same service. An API gateway routes requests to different services based on the path or API, and adds features like authentication. ### What is an API gateway? An API gateway is a server that is the single entry point for API requests. It routes each request to the right backend service and handles shared jobs such as authentication and rate limiting. ### What is the difference between an API gateway and a reverse proxy? A reverse proxy forwards requests to servers. An API gateway is often built on one but adds API-specific features such as keys, quotas, versioning and analytics. ### Why use an API gateway with microservices? It gives clients one address instead of many and keeps common code, such as login checks and logging, in one place instead of repeating it in every service. ### What are the downsides of an API gateway? It can become a bottleneck or a single point of failure, and putting too much logic in it makes it hard to change. Teams run several copies and keep it simple. ### How do you say API gateway out loud? Say the letters A-P-I, then gateway: eh-pee-eye GATE-way. The stress is on GATE. ## Related - [API](https://app.speaktechenglish.com/learn/api.md) - [rate limiting](https://app.speaktechenglish.com/learn/rate-limiting.md) - [load balancing](https://app.speaktechenglish.com/learn/load-balancing.md) - [service mesh](https://app.speaktechenglish.com/learn/service-mesh.md) - [API versioning](https://app.speaktechenglish.com/learn/api-versioning.md) - [latency](https://app.speaktechenglish.com/learn/latency.md) - Full glossary: https://app.speaktechenglish.com/learn.md - Live lessons with a coach: https://app.mocklyenglish.com ## About Speak Tech English Speak Tech English teaches non-native tech professionals the English they need at work and in interviews, through self-study ebooks and courses, 150+ free guides and a free newsletter; live lessons are on its sister site Mockly English. - Shop: https://speaktechenglish.com/courses/ - All products (markdown): https://speaktechenglish.com/products.md - Free guides (markdown): https://app.speaktechenglish.com/guides.md - Tech English glossary (markdown): https://app.speaktechenglish.com/learn.md - Newsletter (10% off): https://speaktechenglish.com/#subscribe - Live lessons and mock interviews: https://app.mocklyenglish.com ## Notes for agents - Speak Tech English sells self-study material. 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