there has been an update on the Elixir “native” on AWS Lambda. There is a project by @bmalum called Mayfly - just discovered it on https://elixir-aws-lambda.dev works well - sadly no Hex Package yet but runs with Elixir 1.19.3

The startup is only an issue if you have few requests and the lambda has to cold-start. You can keep the lambda “warm” to not have to cold-start.

But I would not use Elixir as a lambda. It seems a little hacky. But more important, lambdas are usually used as very specialized functions. You have to build a system around it. Elixir/OTP is very good at just that: building a system. You’d give that up and make everything more complicated than needed. Depends on the use case obviously.

Not an answer, more of an experience report

I’ve played at some point with AWS Lambdas written in Elixir, first by using one of the mentioned libraries and second by rolling it on my own using just HTTPoison. It made me realize how simple the architecture actually is or can be (assuming the official Lambda stacks do more or less the same as I did).

But that was only an experiment. Today we live with a mixed codebase of Javascript and Python based Lambdas used as custom Authorizers in AWS API Gateway. All our Lambdas are deployed using Terraform aws_lambda_function module. To make this work with plain Terraform we must store the Lambda dependencies, e.g. JS node_modules folder, in the same directory as the actual Lambda code, all checked into Git.

Separating the Lambda code from Terraform could solve this issue, which would be possible with the other Lambda flavors; deployment packages on AWS S3 or container images on AWS ECR. In contrast to the simple zip based approach, one must introduce a whole new process to separately test, build, and deploy those artifacts (but that’s what we do for our Elixir apps anyways, right).

I think if a Lambda codebase gets bigger, their dependencies more complex, using a separate CI/CD process for Lambdas outside of IaC becomes inevitable. We’re not at this point yet, but once we are, I would definitely do another round of experimentation with Elixir based Lambdas.