If you have external calls in your integration, you will want to ensure a fast response  

Lambdas - If you are calling FusionAuth APIs in a lambda, ensure a connection over port 9012 (as opposed to port 9011).  Any other external HTTP calls (to your own endpoints) using HTTPConnect should return quickly as well to ensure optimal performance. 

Connectors - If you have a connector, then FusionAuth will hold things in flight (database connections, in-memory information, etc) while we wait for your connector to return an authentication response and log the user in.    

Ideally, your connector would have a read timeout of 1ms and a connect timeout of 2ms or less.   

Higher values mean FusionAuth will have fewer resources (database connections, etc) available to service incoming login requests (as older login requests are still in flight waiting for the Connector return). 

Webhooks -  

If you have any webhooks, these should also return quickly to optimize performance.  Any SocketTimeoutException (read or connect) in the Event Log would indicate a slower webhook integration. 

Adjust Period Tasks  

If you have any periodic tasks running against your deployment (perhaps to synchronize user data, application data, etc by calling our APIs), then you will want to write back-off logic if the system shows a heavy load (monitoring documentation). 

Turn off logging in production  

This change will be less impactful but will help nevertheless.  Logging should be used when there is an issue with SMTP/email, lambdas, connectors, users, etc but turned off in production when not needed.  Logs are output to System > Event Log.  The debug enabled toggle throughout the UI (and API) indicates whether this logging will occur.  

The big ones were that we were making calls to the API in a lambda and switched the port as mentioned. We also had left on debug logging in a lot of places so have disabled that for now. Validated our webhooks are all running pretty fast (median type is 1-2ms) and connector is pretty fast, though slower 20-30ms median.

nslookup login.mycompany.com

Server:         8.8.8.8
Address:        8.8.8.8#53

Non-authoritative answer:
login.mycompany.com       canonical name = mycompany-prod.fusionauth.io.

So should confirm we're using hosted (and had been what I thought).

Though I also see Essentials is under Self-Hosted, so now I'm questioning life. I'll have to check with our DevOps team as well. So will do that (Monday) if there's there anything to look at on our side, let me know.