Poplar offers five mail formats: bi-folds, tri-folds, three different sized postcards, and letters available in Black & White or Color. For your campaign to be considered Active and available for mailing or running test, you must upload a Creative design.
Creative Best Practices.pdf
Creative Best Practices


Bi-folds are available in two different folds: short and long, on silk white paper stock, with two customizable panels on both the interior and exterior:
Example of a Longfold Bi-fold


Tri-fold mailers are also available on silk white paper stock and have three customizable panels on both the interior and exterior:
Bi-fold and Tri-fold formats are only available for static creative designs, and do not yet support dynamic merge tag personalization.


Postcards are currently available in three sizes:
More premium stock options may be configurable and offered for larger monthly volumes
Suggested Use Cases
4" x 6"
Retargeting, Abandoned Cart
Prints and ships the fastest, ideal for short lead times
6" x 9"
Cross-sell/Up-sell, Prospecting
Attention grabbing, small details are easily visible
6" x 11"
Anniversary, Birthday, Celebratory Offers
Highly attention grabbing, fits the most content
6 x 11 Postcard Example

Paper Stock

Poplar offers two postcard stock options:
  • Premium Coated with heavy 120# Super Gloss (14PT) front and light gloss back
  • Premium Uncoated with a matte-like finish and natural paper feel (available for static creatives only)


Windowed envelope with the address info printed on the first page of the letter insert page. Includes the following options:‌
  • 8.5" x 11" letter page inserts. (First page includes area for return and recipient address)
  • Color or B&W
  • Single or Double-Sided
  • Additional pages (charged per page)
  • Return Envelope
  • Perforation (if using Return Envelope)
The white envelope and windowed areas are not customizable - only the return and recipient addresses are visible from the outside.

Supported File Formats

When uploading postcard artwork, you will be prompted to upload two separate files for thee front and back; these files can be a mix of two different supported formats:
For creatives utilizing personalized/dynamic elements.
For designs that remain the same for each recipient.
Only use if you are unable to generate creative in the other formats.

PDF/X-1a and JPG/PNG

Creative files that don't use variable content or dynamic merge tags can be uploaded as static PDF/X-1a or JPG/PNG files. PDF files are recommended for crisp print quality, though JPG/PNG files may be used if you're unable to export your design as a PDF.
When exporting your design to PDF, you must always use Adobe Preset PDF/X-1a. This the most digital print friendly format and will automatically flatten transparencies, adjust to the appropriate color profile, and produce a file that's under 5MB. Visit the link below for more details on best practices and formatting.


Creative designs that use variable content or dynamic merge tags must be uploaded as an HTML file. If only one side of your postcard uses dynamic content, then the other side can bee uploaded as a static PDF or JPG/PNG file.
Web or email best practices for HTML don't necessarily apply to print best practices, so we highly recommend downloading our HTML template files and reading up on dynamic creative best practices at the link below.

Printed Samples & PDF Proofs

If you're interested in receiving a physical sample of your creative before launch, you can do so via the One Time Send option from within your campaign. Select Send Sample, then input the address for delivery:
Depending on mailroom policy, sending to a residential address may be more reliable than sending to an office building.
You'll have a thirty minute grace period to cancel the mailing before it enters the mail stream, to bypass the grace period hit Send Now from the campaign's One Time Send dashboard.
Once the mailing is done processing, you'll be able to see a preview of the mailer along with a delivery date estimate, and live status updates on where it is in the mail lifecycle from production to delivery from the campaign's History tab.

PDF Proofs

During the creative upload process, you'll be given the option to view and download a PDF preview of what your file will look like after cut, with the auto-applied address block:
Always download and review your creative preview to assure all images and text are rendering in high resolution, with no typos or missing elements.
Last modified 1yr ago