What Does API Gateway Do?

What does API gateway do?

The diagram below shows the detail.

Step 1 – The client sends an HTTP request to the API gateway.

Step 2 – The API gateway parses and validates the attributes in the HTTP request.

Step 3 – The API gateway performs allow-list/deny-list checks.

Step 4 – The API gateway talks to an identity provider for authentication and authorization.

Step 5 – The rate limiting rules are applied to the request. If it is over the limit, the request is rejected.

Steps 6 and 7 – Now that the request has passed basic checks, the API gateway finds the relevant service to route to by path matching.

Step 8 – The API gateway transforms the request into the appropriate protocol and sends it to backend microservices.

Steps 9-12: The API gateway can handle errors properly, and deals with faults if the error takes a longer time to recover (circuit break). It can also leverage ELK (Elastic-Logstash-Kibana) stack for logging and monitoring. We sometimes cache data in the API gateway.

Over to you: 1) What’s the difference between a load balancer and an API gateway?

2) Do we need to use different API gateways for PC, mobile and browser separately?

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Alex Xu

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