This is a simple example that shows how to deploy an existing fastify application, with minimal changes, to AWS Lambda.

1. run npm install to grab the dependencies
2. run npm run deploy to send everything up to AWS Lambda

The third step will print out a URL you can use to access the fastify app.

1. Change app.js
2. (Optionally) use npm install <PACKAGE NAME> -S to install additional dependencies (always save them to package.json using -S)
3. Run npm run update to send the new version up to AWS. No need to generate the proxy again

See the Running Express or fastify Apps in AWS Lambda tutorial.