Cold starts, layers, retries

What this card says

Why do we need it?

First invoke after idle feels slow. Shared libs bloat every zip.

What is it?

Cold start = new environment. Layers share libraries. Async invokes retry on failure.

How to do it

Keep packages small; put heavy deps in a layer; design handlers idempotent.

max 5 layers

Example

S3 trigger fails twice then can go to a DLQ you configure.