Example webhook for adding Mailchimp subscribers using AWS Lambda

This is an example of how to create a REST function for lambda that will add subscribers to a mailchimp list.

I'm personally using this for a webhook where the URL is only known by my backend server, so I'm not doing any sort of authentication in this example.

Setup

git clone this project from Github. Modify the following lines of addSubscriber.js:

// datacenter id. find by logging in to mailchimp. ex: https://us19.admin.mailchimp.com/ => us19
const DC = 'usXX';

// create one in mailchimp: Extras => API Keys
const KEY = 'MAILCHIMP_API_KEY';

// your audience id: https://mailchimp.com/help/find-audience-id
// usually a hexidecimal string 10 chars long
const LIST_ID = 'YOUR_LIST_ID';

WARNING: If you fork this to a public repo, make sure not to check in your API key :-).

Then run npm install to install dependencies.

Test Locally

You probably want to run test.js. It's not an entire test suite, but it will determine if you have set up your mailchimp variables from addSubscriber.js correctly.

The file simply will add an email address to your mailing list:

// ...
addSubscriber("[email protected]", "Rocco", "Balsamo");
// ...

Then run it:

node test.js

It should print out a success or error message. If it succeeded, you should verify that the email was added to the list in your mailchimp console.

Deploy

This is a quick-and-dirty method for deploying this lambda function where you will upload code directly to the AWS console via a zip file. There are better ways to do it via command line, but this works without a ton of setup:

1. Follow this tutorial with some modifications TUTORIAL: Build a Hello World API with Lambda Proxy Integration
   • Instead of naming things helloWorld, you may want to name them mailchimpAPI or something similar
   • Use node.js 10.x runtime instead of 8.x that they recommend.
   • When they tell you to name the stage, you might want to put prod instead of test
   • If you want this code accessible from your frontend, you may want to enable CORS, but I have not tested this.
2. Make sure the helloWorld function works for you when calling via curl or the browser.
3. Zip up this code directory, making sure index.js and other files are in the top level of the zip file, not a subdirectory.
4. In the your Lambda function on the AWS console, in the "Function Code" section, pull down the "Code Entry Type" dropdown and select "upload a zip file". Upload your zip.
5. Your API endpoint will look something like this: https://XXXXXXXXX.execute-api.eu-west-1.amazonaws.com/prod/mailchimpAPI

Make sure that you can add a user to the list via an endpoint. Your request should look similar to this.

https://XXXXXXXXX.execute-api.eu-west-1.amazonaws.com/prod/mailchimpAPI?email=someone%40somewhere.com&fname=First&lname=Last

(%40 is uri encoding for @)

Plugs

That's pretty much it! If you liked this example, star it or say hello on twitter! Also check out a website that I run for WebGL games, https://simmer.io.