This serverless function integrates/connects Ghost and ConvertKit through their webhooks and APIs.

The official "integration" for Ghost and ConverKit is a set of Zaps. As they weren't complete enough for my use case and paying for Zapier was too expensive for my personal blog, I created this serverless function to connect the two. This integration (without quotes) is a much more robust integration and easy to customize.

• Sync confirmed subscribers between ConvertKit and Ghost
• Subscribe confirmed Ghost members to ConvertKit sequence (without retriggering another confirmation email)
• Sync unsubscribes between ConvertKit and Ghost
• Sync tags between ConvertKit and Ghost
• Sync resubscribes from ConvertKit to Ghost
• Free deployment to AWS Lambda (compared to more than $20 with Zapier)
• Easy registration of webhooks using custom scripts
• Easy to extend and customize for other needs (create an issue and/or PR!)

The following features are missing because it's not possible to delete members using the ConvertKit API or triggering a resubscribe using ConvertKit.

• Sync resubscribes from Ghost to ConvertKit (other way round should work)
• Sync deletions between Ghost and ConvertKit

• Publish as a stand-alone integration so it is simple to use and install

To deploy or develop this integration, you need the following values and put them into .env:

• CONVERTKIT_API_SECRET: ConvertKit API Secret
• CONVERTKIT_SEQUENCE_ID: ConvertKit Sequence ID (Open the Sequence in the interface and note the last part in the URL, e.g. 1651234 in https://app.convertkit.com/sequences/1651234)
• GHOST_ADMIN_API_KEY API key of a new custom integration. Go to Settings > Integrations and click on "Add custom integration". Copy the Admin API key.
• GHOST_API_URL Copy the API URL from your integration (should be the same as your Ghost blog, e.g. https://www.example.com without the trailing /ghost)

npm install
cp .env.sample .env # Fill in the values from above
npm start

You can use ngrok to locally test the webhooks. In another terminal window, run:

ngrok http 3000

Copy the public URL for the next step of registering the webhooks. It should look like https://abcd-ef-gh-i-jkl.ngrok-free.app.

To register the webhooks, run the following command:

node src/scripts/registerConvertkitWebhooks.mjs

Paste the ngrok URL from the last step and provide a list of tags you want to sync. With ConvertKit, it is only possible to sync tags that were explicitly provided. When you are done, you should see something like the following:

The following webhooks are currently registered:
1001234 | subscriber_unsubscribe | https://abcd-ef-gh-i-jkl.ngrok-free.app/convertkit/subscriber.subscriber_unsubscribe/
1001235 | subscriber_activate | https://abcd-ef-gh-i-jkl.ngrok-free.app/convertkit/subscriber.subscriber_activate/
1001236 | tag_add | https://abcd-ef-gh-i-jkl.ngrok-free.app/convertkit/subscriber.tag_add/finished-yearly
1001238 | tag_remove | https://abcd-ef-gh-i-jkl.ngrok-free.app/convertkit/subscriber.tag_remove/finished-yearly

Repeat this step with the Ghost integration:

node src/scripts/registerGhostWebhooks.mjs

Verify that it worked correctly by visiting the link to your integration that is printed on the console. You should see webhooks for the events member.added, member.edited, and member.deleted.

After completing those steps, ConvertKit and Ghost are integrated through your locally running serverless function. For production use, follow the steps below to run it with AWS.

Setup your AWS credentials before deployment and follow the steps above. Then run the following command:

$ npm run deploy

After deploying, you should see an output similar to this:

Deploying aws-node-ghost-convertkit-integration to stage production (us-east-1)

✔ Service deployed to stack aws-node-ghost-convertkit-integration-production (152s)

endpoint: GET - https://xxxxxxxxxx.execute-api.us-east-1.amazonaws.com/
functions:
  ghost-ck-integration: aws-node-ghost-convertkit-integration-production (1.9 kB)

If you later change the code of the lambda, you can run npm run redeploy for faster deployment.

Register the deployment URL in Ghost and ConvertKit:

node src/scripts/registerConvertkitWebhooks.mjs

# and then afterwards
node src/scripts/registerGhostWebhooks.mjs

If you've set up the webhooks locally, remove them after registering the production endpoint using the following script:

node src/scripts/unregisterConvertkitWebhooks.mjs

For Ghost, it isn't possible to delete the old webhooks programmatically, so you need to visit your integration in Ghost Settings > Integrations > Custom > <Your Integration> and remove them manually.

Enjoy your stress-free no-quotes integration between Ghost and ConvertKit.