For comparison I'm running a low traffic discussion site (https://sqwok.im) with core api through ApiGateway/Lambda w/lots of backend services and it's currently ~$400/month.
The most expensive piece by FAR is Opensearch (previously AWS Elasticsearch) using 6 instances x 2 environments (12 total).
The cost for Elasticsearch in two environments came to ~$371 out of a total $400 bill in my last statement.
The compute cost for Lambda is very low but if you scale out to potentially millions of users it's going to be much more than $100.
Not sure if they're using Opensearch but if they are it's likely a huge part of the bill.
I'm sure there's a better alternative but it's not my particular area of expertise and I haven't been able to focus on that yet.
The most expensive piece by FAR is Opensearch (previously AWS Elasticsearch) using 6 instances x 2 environments (12 total).
The cost for Elasticsearch in two environments came to ~$371 out of a total $400 bill in my last statement.
The compute cost for Lambda is very low but if you scale out to potentially millions of users it's going to be much more than $100.
Not sure if they're using Opensearch but if they are it's likely a huge part of the bill.
I'm sure there's a better alternative but it's not my particular area of expertise and I haven't been able to focus on that yet.