Disclaimer: I work for AWS Professional Services but I just started. All of my experience comes from working at outside companies.

From the perspective of an outside, boots on the ground Developer/architect, I’ve never worried about “vendor lock in”, I believe you should choose your infrastructure wisely and go all in. But, I do worry about “Lambda lock-in” for APIs. I like the optionality of being able to deploy my APIs anywhere just by changing the CI/CD pipeline.

That’s why I recommend using proxy integration. Every language supported by Lambda has a method to just throw your standard API in lambda without tying yourself to it.

Here is an example for Node/Express

https://github.com/awslabs/aws-serverless-express

Python/Flask (ignore the DDB part):

https://www.serverless.com/blog/flask-python-rest-api-server...

C#/Web API

https://aws.amazon.com/blogs/developer/deploy-an-existing-as...