Is there a blog post about the tech stack? My main concern with serverless/lambda is cold start time. How do you deal with it? What does the p99 latency look like?
Also how do you scale the usual bottleneck which is the database?
DB-wise we utilize the usual postgresql cluster setup with read clones in several regions. We could easily partition by course or by org if we had to but honestly we could probably scale up to series C+ before needing to do that.
Out of interest, have you considered moving to a "serverless" db like Aurora Postgres or even DynamoDb, to avoid the cost of unused database capacity at idle times?
I'd love to, but when I've tried to set up Aurora, it seems impossible to do multi-regional with postgresql (not multi-zonal, but multi-regional). Would love to hear how to do this if anyone has got it working. Last time I tried was about 2 years ago.
There is an auto-warming option -- we keep it warmed up every 5 seconds so it's always super peppy -- requests served within 100ms generally, sometimes much faster. Appdex hovers around 0.996 but some webhooks are included in there so it's probably faster in reality.
