Went through three different Shopify product customizer apps before I figured out what was actually going wrong.
Each one had a slick demo. The customer-facing designer looked clean, the preview was convincing, the install was straightforward. First few test orders came through and everything seemed fine.
Then a real customer submitted a real order, and I looked at the output file properly for the first time. JPEG at screen resolution. No bleed. RGB color mode. Essentially a screenshot of what the customer designed, dressed up as a production file.
The app had done exactly what it was built to do — give customers a nice design experience on the storefront. What it wasn't built to do was produce anything a printer could actually use. That gap between the customer experience and the production reality is where most Shopify W2P setups quietly fall apart.
The problem is that most product customizer apps in the Shopify App Store are built for visual personalization — adding a name to a mug, swapping a color, uploading a photo. That's a completely different problem from web to print, where the output file needs to be production-ready. Correct resolution, correct color mode, bleed baked in. The app store doesn't make that distinction obvious, and most merchants only find out after the first order lands in their inbox.
What actually fixed it for us was switching to a solution built specifically around print output rather than customer experience. DesignNBuy's Shopify integration (https://www.designnbuy.com/shopify-product-personalizer/) enforces specs at the template level — bleed, resolution, and color mode locked in before the customer ever starts designing. What comes through on the backend is a file you can send straight to production without touching it.
The customer-facing experience is still clean. The difference is what happens after they hit submit.
If you're running a print operation through Shopify and still manually fixing output files from your customizer, this is probably why. Curious how others here figured this out and what you switched to.