NETWORKING / A CONCEPT NOTE
API Gateway
a single front door for all your backend services
Overview · mechanism
pitfall · examples
01 / THE SHORT VERSION
The idea in a few sentences.
An API Gateway sits between clients and your microservices, handling authentication, rate limiting, request routing, response transformation, and API versioning — so your backend services don't have to. Common implementations: AWS API Gateway, Kong, NGINX, Envoy, and Zuul.
02 / FOLLOW THE MECHANISM
How an API gateway processes a request
Client
sends a request to the gateway's endpoint (e.g.,
https://api.example.com/orders).Gateway auth
validates the API key, JWT, or OAuth token before the request reaches any backend.
Rate limiter
checks the client's usage against its quota. If exceeded, returns
429 Too Many Requests.Router
maps the path
/ordersto the Orders microservice and proxies the request.Response pipeline
the gateway can transform, cache, or aggregate responses before sending them back.
04 / COMMAND NOTES
Read the command, then the result.
Inspect the flags and arguments before trying an example. Snippets can need local setup, replacement values, or resources in your own environment.
check gateway health status
curl -s -o /dev/null -w "%{http_code}" https://api.example.com/healthlist API keys for a usage plan
aws apigateway get-usage-plan-keys --usage-plan-id PLAN_ID05 / CHECK YOURSELF
Could you explain API Gateway to a teammate?
Try it out loud in two sentences: what it is, and the one detail that changes the picture. If you stall, the gap is the part to reread.
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