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Creating Beautiful and Functional Print Mail From Digital Assets
November 3, 2021

Creating Beautiful and Functional Print Mail From Digital Assets

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Sid Maestre

Creating and automating beautiful and functional print mail from digital assets is an important, innovative step toward saving time while getting the most out of all marketing channels. Automating direct mail has been a challenge for many businesses over the years. This article is an excellent start to learning how Lob efficiently solves this challenge.

Lob is a data-driven company that provides user-friendly direct mail and address verification APIs. Digital materials can be converted to print mail assets using the Lob API, saving time and resources. The APIs enable businesses to automate direct mail by helping send personalized mail automatically.

Let’s review a hands-on demonstration of how you can leverage Lob’s APIs to create a postcard from a digital photo.

This tutorial will first guide you through creating a postcard in a very simple way. It is followed by a more technical deep dive into how you can leverage Lob’s APIs to create a physical mail from your digital assets.

Getting Started

We’ll use an image (PNG) to explore Lob and format it for inclusion in a Lob postcard template. First, choose an image you’d like to use (here we'll choose a royalty-free PNG file from Unsplash):

Creating Beautiful and Functional Print Mail From Digital Assets image 2

Then you will need to sign up for a free Lob account. This action directs you to Lob’s dashboard; we will create our postcard here.

Next, we’ll prepare your digital asset (your photo) for print mail.

Prepping your image

As you use Lob, understanding the various mailpiece design formats will help you apply the proper formatting for your files (if not, Lob will throw an error).

Here we’ll use Canva to format the PNG file to work with Lob’s API. To ensure that you produce a PNG file that meets the proper dimensions you'll adjust the file to match the correct size that Lob expects for the PNG file. The Lob dashboard also offers a link to our documentation for image prepping.

TL;DR: an image used to create a 4.25”x6.25” postcard (trimmed to 4x6) should be 1275px x 1875px with a dpi of 300.

Creating Beautiful and Functional Print Mail From Digital Assets image 3

When you have resized your file, export it as a PNG file, and go back to creating your postcard in the Lob dashboard.

Create your postcard

Under Print & Mail, select Postcards. Double-check you are in Test mode (the default), then go ahead and click Create.

Enter a Description, for Size select 4x6, and enter a To and From address. Then it’s time to upload your image.

Creating Beautiful and Functional Print Mail From Digital Assets image 4

From the video snippet above, you can see that editing the PNG file to the expected size allows for a successful upload. Click Create and the result is the rendering of a high-quality postcard that’s ready to be printed and mailed.

Here is the final postcard with our example photo on the front and the photo and postage information on the back.

Creating Beautiful and Functional Print Mail From Digital Assets image 5

Lob will utilize its expansive, always-on print delivery network to print and mail your postcard(s). (Note, to actually send mail, postcards need to be created in Live mode, and you'll need to have payment on file in the dashboard.)

Deep Dive

Now that you have a good idea of the basic functionality, let’s dive in. Using Lob, you can:

  • Programmatically personalize each mailpiece using merge variables in HTML.
  • Convert PDF files into HTML and incorporate PNG and JPG files directly into HTML templates.
  • Use a gallery of HTML templates as a jumping-off point when building Lob templates, or build your own HTML template.
  • Use these easily editable HTML templates at any time with only basic HTML knowledge. We can automatically customize HTML templates for personalized mailings. Also, we can save and reuse HTML templates.
  • Use inline CSS or internal CSS stylesheets. Without CSS, the template appears as a plain HTML page so this option enables you to add some style.

With inbuilt templates, developers and content creators only have to prepare content as an HTML template (allowing for dynamic personalization of each mailpiece), then our APIs do all the necessary heavy lifting to create the physical mailpieces.

You can explore our API documentation here, and learn about pairing Lob’s APIs with Postman. You might also want to check out the series: Create a Postcard with JavaScript. (Part one will create a postcard, parts two and three explain how to integrate our address verification APIs and an introduction to our webhooks for tracking).


In this demonstration, we’ve explored how anyone can leverage Lob’s APIs to prepare physical print mail from digital assets. While here we created just one postcard, Lob is designed to automate direct mail at scale or to integrate with CRMs to send transactional mail.

There are so many possibilities for how you can translate your digital assets with Lob; when you’re ready to send innovative and personalized mail, give it a go.

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