What is API Gateway?
Turkish: API Gateway
An API Gateway sits between clients and services to centralize routing, authentication, quotas, observability, and versioning.
What is an API Gateway?
An API Gateway is a central entry layer between clients and backend services. A mobile app, web interface, or third-party developer sends requests to one address; the gateway routes each request to the correct service and applies shared controls.
This layer can manage authentication, rate limits, quotas, header transformations, logging, metrics, and version routing in one place. In a microservice environment, it prevents every service from reimplementing the same security and observability code.
How It Works
The request reaches the gateway first. The gateway validates the token, checks IP or customer-plan rules if needed, forwards the request according to route configuration, and returns the response to the client. Some gateways also handle response transformation, caching, or request aggregation.
Business Use
As the number of APIs grows, access control and operational visibility become scattered. An API Gateway centralizes traffic management, but it should not become the place where all business logic lives. The gateway should enforce shared edge policies while core domain rules remain in services.
For SaaS and mobile backend projects exposing REST APIs, gateway choice should be evaluated through latency, plugin ecosystem, deployment model, and observability integrations.
Related Terms
API Gateway security centralizes authentication, quotas, WAF rules, and traffic visibility at the API entry point.
API QuotaAn API quota limits the total calls, data volume, or operations a customer, application, or key may use within a defined period.
Rate Limiting StrategiesRate limiting strategies balance API request speed with fixed window, sliding window, leaky bucket, or token bucket algorithms.
API (Application Programming Interface)An API is a contract that lets software systems request approved data or actions from one another through documented endpoints.
Backend for FrontendA BFF creates a separate backend layer for web, mobile, or other interfaces, shaping API responses for each client.
MicroserviceMicroservice architecture designs a large application as small services that can be developed, deployed, and scaled independently.
Rate LimitingRate limiting protects APIs by capping how many requests a user, IP address, or token can send within a defined time window.
REST APIA REST API designs web services around resources and HTTP methods, making integrations predictable across web and mobile systems.
Reverse ProxyA reverse proxy sits in front of backend servers, routing client traffic while handling TLS termination, caching, security, and load balancing.