Running Express Applications on AWS Lambda and Amazon API Gateway

Express is a web framework for Node.js . It simplifies the development of “serverless” web sites, web applications, and APIs. In a serverless environment, most or all of the backend logic is run on-demand in a stateless fashion (see Mike Roberts’ article on Serverless Architectures for a more detailed introduction). AWS Lambda, when used in conjunction with the new Amazon API Gateway features that I blogged about earlier this month (API Gateway Update – New Features Simplify API Development), allows existing Express applications to be run in serverless fashion. When you use API Gateway you have the opportunity to take advantage of additional features such as Usage Plans which allow you to build a developer ecosystem around your APIs, and caching which allows you to build applications that are responsive and cost-effective.

In order to help you to migrate your Express applications to Lambda and API Gateway, we have created the aws-serverless-express package. This package contains a working example that you can use as a starting point for your own work.

I have two resources that you can use to migrate your Express code and applications to API Gateway and Lambda:

• Running Express Apps in AWS Lambda shows you how to use Claudia.js and the aws-serverless-express module to deploy your application. You simply remove the existing TCP listener, create a Lambda proxy wrapper, and deploy!
• Going Serverless: Migrating an Express Application to Amazon API Gateway and AWS Lambda goes in to a bit more depth than the previous post. For example, it shows you how to set up environment variables,  manage database connections, and provides some guidance on efficient hosting of static assets. The post also details the entire release process and introduces some other Lambda and API Gateway features that might be of interest to you.

— Jeff;