What is the cheapest way in AWS to return an HTTP 200 to a client?

Question

I was having a discussion with some fellow developers today and this came up. Sometimes before retiring an api you may need to return an HTTP 2xx to a client to avoid errors for a short period of time.

I was thinking possibly an HTTP Lambda might be the cheapest but I'd love some feedback.

Answer

If you're using API Gateway then you can create a [mock endpoint](https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-mock-integration.html) that returns 200 without executing anything else. You only pay for the requests that you make and you may be eligible for the free tier: https://aws.amazon.com/api-gateway/pricing/

Answer

It depends. If the APIs has crazy throughput Lambda may not be cheap after all. If access is infrequent then yes.

Another idea could be to use S3, where you would host a dummy HTML page that would return 200. Depending if it has a Cloudfront distribution in front of, it may be a hack but definitely cheap too.

What is the cheapest way in AWS to return an HTTP 200 to a client?

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