AWS has its own Serverless Application Model (SAM) https://github.com/awslabs/serverless-application-model released last Oct. Rather than learning another framework, you'd use the same CloudFormation yaml syntax to define your stack and apps. It simplifies calling Lambda functions by providing a higher level abstraction triggers called Events. This makes it simpler to create Lambda functions for Rest API, Cron schedule, IoT devices, create Alexa skills, response to S3 events etc. Then its just "aws cloudformation package" and "aws cloudformation deploy" to create and update your app. It appears AWS team is learning the best from Serverless Framework. If you not mind the vendor lockin, SAM is the way to go. Serverless Framework has the promise of using the same tool against AWS Lambda, Google/Azure Functions and IBM OpenWhisk.

We started with Serverless as well, but as soon as we started to do more complex stuff it showed its limitations and we ended up writing lots of CloudFormation resources in serverless.yml. That was no benefit over pure CloudFormation anymore, especially as Serverless uses YAML, but relies on some notations from JSON-CloudFormation templates, I assume because it pre-dates the introduction of YAML for CloudFormation templates. In the end we switched over to CloudFormation with SAM (Serverless Application Model) and while that also still has some rough edges, we have been pretty happy since.

So if you don't rely on the cross-provider features Serverless offers I suggest to take a look at CloudFormation + SAM instead.

Agreed, at first I was skeptical because the marketing message on the site seemed a bit over-hyped, but it turns out it is a really valuable tool for streamlining both testing (invoke local) and deployment when working with Lambda. New users also benefit for the basic scaffolding (severless create) and the documentation is pretty decent.

I have tried kappa (Python) and node-lambda (Node.js), and serverless works better than both of them, is more frequently updated (Lambda and API Gateway themselves change frequently), supports more languages (I have used it with Java, Python and Node.js) and has a much larger, more active community.

The API gateway support is pretty simple and solid, and they also allow you to use cloud formation rules directly so it is very flexible.

I tried to use serverless, but I don't have full admin permissions and the site is unable to say what permissions it actually requires to work. I'll swing back round to it later in the year and see how it's progressing.