Is it possible to set up a 3% fee for credit card payments to charge to the future guest automatically?

Yes. You can add a percentage fee that is charged automatically on every booking.

1. Go to Menu > Manage Listings > Edit > Pricing > Rates & Fees, open the Additional Fees section, and click Add a fee.

2. Give it a name the guest will see, such as Card Processing Fee.

3. Enter 3 as the Amount and set Type to Percentage (%).

4. Tick On Total so the 3% is calculated on the booking total.

5. Leave (optional) unticked - that is what makes it charge on every booking rather than being something the guest can decline.

6. Click Add Fee.

It saves straight away and appears on your listing's price breakdown.

One thing worth weighing first: the reason many travellers book direct on Houfy is to avoid the extra fees they see on other platforms, so some hosts prefer to build the processing cost into their nightly rate instead of showing it as a separate line.

Also check your state's laws - some states restrict passing card fees on to consumers.