What's documented is that memory is billed for as long as the environment is active. What's not documented is how long those environments actually remain alive after their last request, and there's no configurable idle timeout.

And for context, Easel.sh is an alternative to Vercel, not AWS. Easel actually uses traditional Lambda as part of its core infrastructure. I was hoping Web Functions could replace some of the custom infrastructure we'd built on top of it, but the idle-memory billing made it a poor fit for our workload.

I thought the findings were worth sharing.