A subscription processor that passes interchange at cost with a 0% percentage markup, billed as a flat membership.
Best for
Higher-volume US merchants (around $150K a year and up) who win on a fixed-margin subscription model.
Every fee we track, grouped by where it applies.
In-person terminal and tap-to-pay transactions.
Subscription model: 0% percentage markup, interchange passed at cost, plus 8c/tx in person. The percentage estimate is 0 because the margin is the flat membership fee, not a percentage.
Entry membership (up to $150K/yr). $139/mo to $250K, $199+/mo above.
No setup fee published; verify.
Online checkout and keyed-in card transactions.
Online/keyed: 0% markup + 15c/tx, interchange at cost.
Entry membership (up to $150K/yr). $139/mo to $250K, $199+/mo above.
No setup fee published; verify.
Reported; not transparently published. Verify.
30 days notice; no ETF.
Verify.
No separate PCI fee.
Stax Pay platform: recurring, invoicing, hosted pages.
Cards, wallets, and other methods supported by Stax for US merchants.
Stax (formerly Fattmerchant) uses a subscription model: you pay a flat monthly membership and the card networks’ interchange at cost, with no percentage markup on top, just a small per-transaction fee. For higher-volume merchants this can be significantly cheaper than a flat rate, because the processor margin is fixed rather than scaling with your sales.
The membership tiers step up with annual volume, and the model only makes sense once you are processing enough to outweigh the monthly fee. Hardware is quoted rather than published, and the platform includes invoicing, recurring billing, and hosted payment pages.
Stax was founded in 2014 and is headquartered in Orlando, USA.
Side-by-side with the closest alternatives by estimated cost.
Assumes $15,000/mo volume, $50 average transaction, 70% in-person and 30% online.
Stax
$129/mo est.
Helcim
$104/mo est.
PayPal
$438/mo est.
Chase Payment Solutions
$447/mo est.
The same questions US merchants ask before signing up.
Stax uses a subscription model. You pay a flat monthly membership of $99/mo and the card networks' interchange at cost, with no percentage markup on top, just a small per-transaction fee shown as 0% markup + 8c in person and 0% markup + 15c online. The membership tier steps up with your annual volume.
Stax pays off once you process enough volume to outweigh the monthly membership. Because the processor margin is a fixed fee rather than a percentage, higher-volume merchants (roughly $150K a year and up) often save meaningfully versus a flat rate. Below that volume the membership can cost more than you save, so check the calculator on this page against your numbers.
No. Stax is month-to-month with no long-term contract and no early termination fee, requiring only standard notice to cancel. That removes the lock-in risk that some subscription and reseller-based processors carry, so you can leave if the volume math stops working for you.
A flat-rate processor like Square charges the same percentage on every sale, so the processor's margin grows as your sales grow. Stax instead charges interchange at cost plus a fixed monthly membership, so its margin stays flat no matter how much you process. That makes flat-rate cheaper at low volume and Stax cheaper at high volume.
Yes. The Stax Pay platform includes recurring and scheduled payments, invoicing, and hosted payment pages across all membership tiers. That makes it a workable option for businesses with subscription revenue that also want the fixed-margin subscription pricing model.
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