There is nothing inherently asynchronous about the Lambda product, unless you’re talking about the Node.js runtime and even then that’s more about Node than about Lambda.

Each Lambda invocation gets a dedicated VM for the duration of the request. It is a great match for synchronous code.

That is a mis-statement. Lambda executes functions in response to events. It is totally asynchronous with regards to its execution triggers.

Lambda does reuse VMs, so I hope you aren’t relying on containers being discarded for any integrity or security outcomes.

All the responses in this thread illustrate to me that AWS needs to put more effort into socialising how the product works. Since I was physically in the room for Lambda’s AWS internal launch this is twice disappoint because the technical messaging then was very clear and compelling.

Lambda is natively http based, no? Like all aws apis. It's just that it only speaks it's own json protocol, not generic web.

Also request/response is not inherently synchronous or asynchronous. It's just a protocol design pattern.

Buffering, overcommit, etc are also kust normal facts of life in both sync and async messaging.

No, it it natively event driven. Don’t confuse the control plane for the operational.

Request/response is fundamentally synchronous. If you want to nitpick about other layers not blocking, that’s missing the wood for the trees.

I would read a deep dive blog post about this.