What is Opensend Postal and how do I use it?

Direct mail is one of the most effective ways of retargeting website visitors. With Opensend Postal, you can have postcards sent to your visitors, with Opensend providing the physical address, then printing and shipping the card for you.

What is Opensend Postal?

Opensend Postal is a service that will find physical addresses and send postcards to a subset of your website visitors - based on criteria you define (i.e. anyone who abandoned a cart). Taking advantage of Opensend Postal is easy, and each of these steps is outlined in more detail below:

  • You will design and upload the postcard template into Opensend.
  • You define criteria (typically within your existing marketing platform) of who should get a postcard - those profiles will be uploaded to Opensend in real-time via API. All you need to give us is an email address.
  • Opensend will lookup the physical address, based on the email address, and then send a postcard to anyone whose address we can identify.
  • Start small or big, the choice is yours! Purchase packages of postal credits, with built-in bulk discounts, that you can set to auto-reload when you run out.

What visitors are good candidates to send postcards to?

You can decide on what audience should receive postcards! If you're not sure where to start, we recommend targeting visitors who abandon a cart or a checkout without making a purchase.

How do I prepare and upload a Postcard on Opensend?

Please follow the below requirements to prepare your postcard to upload on Opensend:

  • Need guidance on how to design a good postcard? Follow these best practices.
  • The Postcard needs to be in PDF format.
  • The PDF file should have page dimensions of 6.25 Inches(width) x 4.25 Inches(height).
  • The PDF file should contain two pages. The first page is for the front of the postcard and the second page is for the back of the postcard.
  • Here is the sample Postcard PDF file you need to follow.

Please follow the below requirements to upload your postcard to upload on Opensend:

  • Go to the “Postal” tab from the Opensend Dashboard
  • Click on “Postcard configuration”

  • Click on "Upload a PDF" and add the Postcard file you want to send to your contacts from Opensend.
  • Click "Submit"
  • Please make sure that the "Postcard" toggle is turned on from the top.

How do I integrate my marketing platform with Opensend for Postal?


You will need to get the following information from Opensend Dashboard:

  • Webhook URL: https://api.opensend.com/postal/postcard
  • Integration ID: Go to the “Postcard configuration” tab and copy it from there
  • Postal API key: Please follow this guide to get your API keys

Integration using Webhooks:

You can integrate your email marketing platform with Opensend using Webhooks. If you want to integrate with Opensend Postal API directly, you can follow this guide.

We are going to demonstrate an example using Klaviyo on how to integrate your Klaviyo account into Opensend Postal.

  • Go to Klaviyo Dashboard
  • Click on "Flows"
  • Click "Create from Scratch"
  • Add a name for your flow (It can be Opensend Postal)
  • Click "Create Flow"
  • Select the trigger as per your choice e.g. if you want to send a Postcard to the customer who placed an order you can select "Placed Order" as the trigger
  • Add webhook as the next step in the flow
  • Use the following configuration in the webhook:
    • Destination URL:
    •  Add a header:
      • Key: x-api-key
      • Value: Postal API key you copied from the dashboard
    • JSON body :
      "integration_id": "Integration ID you copied from the dashboard",
      "email": "{{ person.email }}"
    • Click "Save"
  • Click on "Review and turn on"
  • Select "Live" as the Action status
  • Finally, Click on "Turn on"

How do I purchase Opensend Postal credits?

  • Go to the “Postal” tab from the Opensend Dashboard
  • Click on “Buy Packages”
  • Click on "Buy More Credits"
  • Click "Select" under your desired Package and proceed to make the purchase

  • Once you complete the purchase, you will have credits available in your account to service the Opensend Postal.
Enable Auto-renewal of Opensend Postal Credits:
Note: If you don't want the Opensend Postal to automatically renew you don't need to take any additional steps.

For auto-renewal of your Opensend Postal credits follow these steps:
  • Enable the "Auto reload when out of credits" toggle
  • Select the package you want to enable for auto-renewal