Launched foldcardpdf — free, browser-only fold-card PDF maker

Just shipped foldcardpdf.com — a free browser tool I built to make the print-and-fold greeting card workflow less painful.

What it does: drop in up to 4 images, pick card size and paper, download a print-ready PDF. Everything runs in the browser via pdf-lib + Canvas — no signup, no upload, nothing leaves your machine.

The part I'm proud of is the duplex-drift fix. Most home duplex printers have a 1–3mm offset between front and back of the page that makes fold cards look misaligned. There's a one-time calibration step (print a test page, measure the offset, type it in) and every PDF after that compensates. Took my own cheap printer from "unusable for cards" to "looks bought from a store."

Origin story: I make pet sympathy cards on the side and got tired of redoing the layout in design software for every order. Built this for me first; sharing it free because the duplex-drift problem affects way more than just my niche.

Would love feedback from anyone here who's printed at home enough to recognize the drift problem — or honestly any feedback at all. What would make it useful for your workflow?