Payment processor

A payment processor is the plumbing behind every card swipe, tap, or online checkout: when a guest pays, the processor carries the transaction from their card to the networks (Visa, Mastercard) to their bank, gets it authorized, and settles the money into your account, usually the next business day. In a restaurant this function is almost always bundled into your Point of sale (POS) (for example Toast or Square for Restaurants) or handled by a dedicated processor such as Shift4 or Heartland Restaurant.

It matters because it is a permanent tax on revenue. Every transaction carries a fee, typically in the 2 to 3 percent range, split between the Interchange fee the card networks charge and the processor's own markup on top. On a 3-5% net margin business those pennies add up fast, and the way the fee is quoted (a flat blended rate versus interchange-plus, where the markup is shown separately) determines whether you can even see what you are paying. Card volume runs enormous at scale: Toast alone processed $51.5 billion GPV in a single quarter.

The practical caution for an independent is that bundled processing is convenient but locks you in: the smart features and the card rate come from the same vendor, so switching one means switching both. Ask any provider for your effective rate (total fees divided by total card sales) and watch it over time, because that single number is the honest cost of accepting cards.