Uploading Creative

Once you've created your campaign, the next step is uploading your creative files. Creative must be uploaded before a campaign can be considered active for integration testing. There are two different types of creatives: Static (PDF, PNG/JPEG - not compatible with merge tag personalization) and Dynamic (HTML/CSS - for designs with merge tag personalization). Before uploading, double check your files to make sure:

  • Your files are separated into Front and Back - the address block will be auto-applied to the back.
  • Your design is edge-to-edge and does NOT have a white border, crop marks, or a placeholder/white box where the address block will appear.
  • There is a 0.125in bleed on all four sides, bringing your total file dimensions to 4.25 x 6.25, 6.25 x 9.25, or 6.25 x 11.25 postcards only
  • All images used are high resolution (300 DPI/PPI) and your file is PDF/X-1a static creative only

Visit our Static and Dynamic creative guides for more info on best practices and export instructions. If you'd like to use dynamic merge tags in your design but aren't proficient in HTML or CSS, Poplar offers complimentary creative translation services to turn your static design into dynamic HTML. Learn more and submit your request here:

Creative Translation Request Form


Start by clicking into your campaign and navigating to the Creative tab, then click New Creative in the top right to begin:

Creative Selection

First, you'll see the option to select the creative format that aligns with your design files. Then you'll be prompted to give your creative a unique name:

Creative Selection

Bi-fold and Tri-fold formats are currently in private beta, please reach out to support@heypoplar.com for more info.

Next you'll select postage speed and paper type. USPS Standard shipping typically reaches homes within 7-15 business days (Monday-Friday), where USPS First Class can start to hit homes between 5-7 business days from launch - see a breakdown of our production and in-home timelines here. These estimates are subject to change considering federal holiday closures and on USPS back-log during major holidays. Our 4 x 6 and 6 x 9 postcard formats have first class shipping baked into the base price, but as you switch between formats and shipping speeds you'll notice the price per-piece calculate in the top right.

Poplar offers two paper stock options: premium coated and uncoated:


Premium Uncoated currently only supports static PDF/x1a creative designs and is not available for HTML creatives using dynamic merge tags - reach out to support@heypoplar.com for more info.

Upload Creative

If you selected one of our postcard formats, you'll be prompted to drag & drop your front and back files into the platform for upload. The address block will be auto-applied to the back, so make sure the uploaded files are in the correct order. If you selected a letter, bi-fold or tri-fold format you'll be prompted to upload a single file - if your letter has multiple pages or is double sided, make sure all pages/sides are within a single PDF or HTML file. Other key items to consider during upload:

  • Supported file formats: PDF, PNG, JPG, HTML
  • Maximum file size: 5MB

Upload Creative

Front and Back files do not need to be the same format - if only one side of your postcard uses dynamic merge tags, the other side may be uploaded as a static PDF/X-1a file.

Set Merge Tags HTML Only

If your dynamic HTML creative contains any custom merge tags, you'll be prompted to set a default value as a fallback in the event of blank data. These fallbacks are for custom merge tags only. If your creative contains default merge tags (such as first name) or a promotion merge tag this step will be skipped - this is not an indication the merge tags are missing from the creative. You have the option to opt out of setting a default value if a fallback isn't applicable, but we definitely recommend setting one whenever possible.

Set Merge Tags

Liquid logic can be used to set a fallback value for first name default merge tags, if you don't have first name data for every recipient on your list. If a fallback isn't set, "Current" (as in "Current Resident") will end up populating the merge tag. Promotions merge tags don't need a fallback because mailers will automatically stop sending once the list of codes runs out.

PDF Proof: Review & Finalize

The final step in the upload process is reviewing the PDF proof of the final product after trim, with the address block and default merge tag data applied. ALWAYS closely review your proof by downloading it and opening the file outside of the browser, here are a few key things to look for:

  • Spelling errors, typos, blurry images or text, missing promo codes or QR codes
  • Make sure the address block is on the correct side and not covering any important text or images
  • Double check expiration dates are at least 30 days from the launch date
  • No text is being cut off or running too close to the edge


Creatives may take a number of minutes to render, but if end up stuck on this step and unable to finalize please reach out to support@heypoplar.com for assistance.

Creative Overview

Click into your creative to see an overview of the Creative Details and to access functions such as Edit Creative, Set as Default, Deactivate Creative, download Uploaded Artwork files and Proofs. Towards the bottom of the page you'll see a list of all merge tags present in the creative, any promotions the creative is connected to, and Data Guides for CSV and API templates.

Edit Creative

This allows you to edit the Creative Name and Shipping speed ONLY. Any other updates such as paper type, size, or file edits will require uploading new creative and deactivating the old one.

Set as Default

If you're running a triggered campaign and want to fire one specific creative, you may do this by setting it as the default. When a default is set, you do not need to include creative_id in your webhook trigger - if creative_id is set in your webhook it will override the default setting. If you're looking to A/B test multiple creatives, make sure a default is not set and the platform will automatically randomize between all active creatives under the campaign.

Deactivate Creative

Deactivating a creative renders it inactive for mailing. This means if you have any active webhook triggers pointing to an inactive creative_id, mailings will stop firing.

Creatives must have unique names so if you plan to upload new creative with the same name, make sure to rename the creative before deactivating.

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