Postcard Designs & Templates
How to Design a Proof Postcard
A Proof postcard leads with verified evidence, such as customer numbers, local work, adoption or another documented result, so the recipient's first impression is a result rather than a claim. Design it around one piece of evidence you can substantiate and one call to action.
Practical guide · Published September 20, 2026 · Written by Jeffrey Huis in 't Veld
What counts as proof
Proof is anything that reduces the recipient's uncertainty about whether you deliver, and that you can document. Common forms include the number of customers or users, work completed nearby, adoption within the recipient's industry and a specific result a customer achieved. A vague statement like "trusted by leading companies" is not proof, because the recipient has nothing to check.
Verifying before you print
Before any number or claim goes on a card, confirm where it comes from, that it is current and that you have permission to name any customer. If you cannot point to the source, leave it out. An unverifiable figure can cost more credibility than having no figure at all.
What goes on the front and back
On the front, lead with the evidence itself, stated as a specific fact, with a badge if it helps. Keep the supporting line short. On the back, explain what the evidence means for the recipient, then end with one call to action next to a QR code. The recipient should be able to connect the proof to their own situation in a few seconds.
An example
For the hypothetical scheduling software company, a Proof postcard might open with a verified statement about how many clinics use the product, or about clinics the company already serves in the recipient's region. The back would say what that could mean for the recipient's schedule and invite them to see it. Any real version needs a number the company can substantiate.
Common mistakes
The usual mistakes are using vague superlatives, stacking several unrelated statistics, presenting old numbers as current and naming customers without permission. Another is leading with proof that has nothing to do with the recipient. The evidence should be relevant to the reader's industry, size or location.
When to choose a different design
If you have no evidence you can verify yet, start with an Introduction or an Offer. If the list is small and warm, a Personal Note may build trust more effectively than statistics. Proof suits skeptical audiences and crowded categories, where the main barrier is doubt.
Customizing your Proof postcard
In Yotru you can edit the greeting, headline, supporting line, badge and QR text, choose the landing page, swap the photo and adjust the logo and colours. On the back you can change the message, sign-off, optional points and contact details. Insert first name, last name, company or city to make the evidence feel relevant to each recipient.
See four postcard concepts for your company.
Frequently asked questions
Customer or user numbers, work completed near the recipient, adoption in their industry, or a specific documented customer result. Anything you cannot substantiate should be left off.
Only with their permission. Where you don't have it, use a documented figure or describe the type of customer without naming them.
Choose a different design. An Introduction or Offer postcard does not depend on statistics, and you can add Proof later once you have evidence you can verify.
Related topics
Work with Yotru
See four postcard concepts for your company.
Start with your website and Yotru builds four editable concepts: Introduction, Offer, Personal Note and Proof.