I use API Gateway to provide an API endpoint powered by Lambda (and deployed via Serverless). It took a few hours to understand the relationships between Gatewa

I use API Gateway to provide an API endpoint powered by Lambda (and deployed via Serverless). It took a few hours to understand the relationships between Gateway and Lambda, the wire a custom domain names with HTTPS, but ones you understand its operating model it runs very well. 'Cold starts' is a complicated topic. AWS will keep your Lambda 'hot' for ~5 minutes since the last invocation - you are not paying for the 5 minutes, but it still sits in their RAM waiting for requests. This means that any request within 5 minutes of the last request does not pay the cold-start price. So I used Pingdom to monitor/ping the endpoint every 5 minutes, thus keeping one instance of the function perpetually 'hot'. Note that this hack will not work if you need high concurrency: you can only keep 1 instance alive. In practice, it's enough for us as one instance can serve most of the traffic in our case.