Stax
Payments Verified May 2026
Stax deal: Flat monthly fee + 0% markup (interchange only)
Subscription-based payment processing — pay a flat monthly fee and 0% markup on interchange, so high-volume merchants keep more of every sale.
- True interchange+ pricing means you pay actual card network cost — no markup
- Predictable monthly cost instead of variable percentage fees
- Best value at mid-to-high volume ($200K+ annually) vs flat-rate processors
- Transparent fee structure eliminates surprise charges
How Stax scored 70/100
6 weighted criteria, each scored out of 10 and published with its reasoning. Featured placements never move a score.
Deal Strength
8.0 /10The offer is the pricing model itself: a flat monthly subscription plus 0% markup on interchange, so merchants pay wholesale card-network rates rather than a percentage of every sale. There is no exclusive coupon here, but for a higher-volume business that structure is worth far more than any one-off promo code.
Value for Money
8.0 /10Stax pays off strongly above about $10k in monthly card volume, where interchange-plus billing commonly cuts total processing costs 20-40% versus flat-rate processors like Square. Below roughly $5k a month the fixed $99+ membership works against you, so the value is genuinely excellent only for the volume tier it targets.
Capability
8.0 /10Stax is a full merchant-services platform, not a single reader: in-person, online, mobile, invoicing, recurring billing, ACH, surcharging, a virtual terminal, QuickBooks integration and a reporting dashboard all sit inside one subscription. Few functional gaps for a US SMB, though it lacks the sprawling app marketplace of a Stripe-style developer stack.
Time to Value
5.0 /10Expect roughly 5-10 business days from application to live processing, since Stax runs real underwriting and business verification before approval. That is slower than the instant self-serve signup of Square or Stripe, but normal for interchange-plus providers that price each merchant on actual risk and volume.
Trust & Reliability
5.0 /10Stax is an established Orlando-based processor, founded in 2014 as Fattmerchant and rebranded in 2021, with PCI-compliant infrastructure across its stack. It is a credible, actively developed company, but it publishes little on uptime SLAs and independent support reviews are mixed, so this sits at solid-but-unproven rather than best-in-class.
Flexibility & Exit
5.0 /10Billing is refreshingly clean: month-to-month terms, no long-term contract and no cancellation fee, so you are not locked in on paper. The real friction is practical, since leaving any processor means re-underwriting elsewhere and migrating terminals and integrations, and Stax serves US merchants only.
Flat monthly fee + 0% markup (interchange only)
Affiliate link — same price for you, and it never moves the score.
- True interchange+ pricing means you pay actual card network cost — no markup
- Predictable monthly cost instead of variable percentage fees
- Best value at mid-to-high volume ($200K+ annually) vs flat-rate processors
- Transparent fee structure eliminates surprise charges
About Stax
Quick answer
Stax (formerly Fattmerchant) is a subscription-based payment processing platform. Instead of charging a percentage markup on every transaction, Stax charges a flat monthly membership fee and passes through interchange at 0% markup — so high-volume merchants keep far more of each sale. It’s built for established small-to-mid businesses processing enough volume that percentage fees genuinely hurt. Pricing is a flat monthly subscription plus direct-cost interchange.
What is Stax?
Stax is a payments company built around a different pricing model. Most processors (Stripe, Square, PayPal) charge a blended percentage — roughly 2.6–2.9% + a fixed fee — on every transaction, which scales painfully as your volume grows. Stax instead uses subscription pricing: you pay a fixed monthly membership and then only the true interchange cost set by the card networks, with 0% processor markup.
On top of the pricing model, Stax provides a full payments platform: in-person terminals and POS, online and invoice payments, recurring billing, a customer database, and analytics. The result is aimed at established businesses where the membership fee is easily outweighed by the markup they stop paying on high transaction volume.
Key features
Subscription pricing
Flat monthly fee with 0% markup on interchange — no per-transaction percentage.
Omnichannel payments
Accept in-person (terminals/POS), online, mobile, and invoice payments.
Recurring billing
Subscriptions and scheduled payments with stored cards.
Invoicing & links
Send branded invoices and payment links to get paid faster.
Analytics dashboard
Track sales, deposits, and customer data in one place.
Integrations
Connect to accounting and business tools, plus an API.
Stax pricing explained
How much does Stax cost? Stax charges a flat monthly membership (tiers typically scaling with processing volume and features) plus the raw interchange set by Visa/Mastercard — with no added percentage markup and a small per-transaction fee. The break-even logic is simple: once your monthly card volume is high enough, the markup you’d pay a flat-rate processor exceeds Stax’s membership, so you save. Below that threshold, Square or Stripe’s no-monthly-fee model is cheaper. Confirm current membership tiers and the break-even volume for your business.
Stax vs Stripe vs Square
| Processor | Best for | Pricing | Standout |
|---|---|---|---|
| Stax | Higher-volume merchants | Subscription + interchange | No % markup = big savings at volume |
| Stripe | Online/developers | ~2.9% + 30¢ | Best APIs, no monthly fee |
| Square | Small/in-person | ~2.6% + 10¢ | Simple, free to start |
✓ Use it if you
- Process high monthly card volume
- Want to stop paying percentage markups
- Value transparent interchange-plus-zero pricing
- Run an established business with steady sales
✗ Skip it if you
- Are a low-volume or new business (flat-rate is cheaper)
- Want no monthly fee (Square/Stripe)
- Need the deepest developer API (Stripe)
- Process only occasional payments
Is Stax worth it?
Is Stax worth it? For established, higher-volume merchants, yes — the subscription model with 0% markup on interchange can save real money compared to the percentage fees of Stripe or Square, and you get a full omnichannel payments platform alongside it. The decision is purely mathematical: above a certain monthly processing volume, the membership fee is cheaper than the markup you’d otherwise pay, so Stax wins; below that threshold, flat-rate processors with no monthly fee are simpler and cheaper. If you’re processing enough that card fees are a noticeable line item, get a Stax savings quote — the break-even math usually favors it.
What's included
- Flat-rate pricing favors high-ticket transactions
- Invoicing and recurring billing bundled in
- Fast onboarding for verified businesses
- Transparent pricing with no hidden tiers
- SaaSTweaks-verified affiliate deal
- Vendor-direct activation flow
- Editorial pros + cons review
- Tracked savings claim with refresh date
Stax pricing
Verified May 2026. Vendor's published rates at the time we checked — always confirm at checkout.
| Plan | Price | Term | What you get |
|---|---|---|---|
| Growth | $99/mo | up to $500K annual volume | Interchange+ pricing · No per-transaction markup · In-person, online, mobile · Free card reader · Next-day deposits |
| Pro | $159/mo | up to $1M annual volume | Everything in Growth · Advanced reporting · Multi-user access · QuickBooks integration · Dedicated support |
| Ultimate | $199+/mo | custom volume | Everything in Pro · Custom volume pricing · Account manager · API access · Advanced integrations |
How to claim it
4 steps. The last one is the part most people skip.
- 1
Open Stax through the link on this page
It carries our referral tag. The price you pay is identical either way, and it never changes the score on this page.
- 2
Pick the plan that matches your usage
This offer applies automatically through the link — there is no code to enter.
- 3
Confirm the discount before you pay
The order summary should show the reduced amount. If it does not, stop and tell us — we re-test listings that stop working.
- 4
Check what happens at renewal
Note the renewal date and the rate it reverts to, so the second invoice is not a surprise. Annual plans are usually cheaper per month but harder to exit.
Where Stax wins and loses
What works
- True interchange+ pricing means you pay actual card network cost — no markup
- Predictable monthly cost instead of variable percentage fees
- Best value at mid-to-high volume ($200K+ annually) vs flat-rate processors
- Transparent fee structure eliminates surprise charges
What doesn't
- Fixed monthly fee means higher effective cost at low transaction volumes
- Not worth switching below ~$10K/month in card volume vs Stripe flat rate
- Interchange+ requires understanding card type fees (different rates per card)
- US-focused — limited international payment support
The bottom line
Stax swaps the usual percentage markup for a flat monthly membership and pure interchange-plus pricing, which turns into real savings once a business clears roughly $10k a month in card volume. Thinner public proof on support and uptime keeps it a confident buy for higher-volume merchants rather than a universal pick.
Stax charges a flat monthly membership instead of a percentage of sales: about $99/month for up to $150k in annual card volume, $139/month up to $250k, and $199+/month above that. On top of the subscription you pay actual interchange plus a small per-transaction fee, roughly 8 cents card-present and 15 cents card-not-present, with 0% markup on the interchange itself.
Interchange-plus means you pay the wholesale rate card networks set (the interchange), plus a defined fee on top, with nothing hidden. Stax takes this further with a subscription model: its 'plus' is a flat monthly membership and a few cents per transaction rather than a percentage markup, so your processor's cut stays fixed even as your sales grow.
Stax is worth it for businesses processing more than roughly $10k a month in cards, where subscription pricing typically cuts total processing costs 20-40% versus flat-rate providers. For very low-volume merchants the fixed membership outweighs the savings, so a pay-as-you-go option like Square is usually cheaper until you scale.
Square charges a simple flat percentage per sale and is cheaper for low volume and instant to start, while Stax charges a monthly membership plus raw interchange and wins on cost at scale. The crossover sits around $5k-$10k in monthly card volume; above it Stax's flat-fee processing saves more, below it Square is the better value.
No. Stax now offers month-to-month terms with no long-term contract and no cancellation fee, so you can leave without an early-termination penalty. The practical cost of switching is operational rather than contractual, since moving merchant services means re-underwriting with a new processor and migrating your terminals, integrations and recurring-billing setup.
No, Stax operates only in the United States and does not onboard international merchants. Businesses elsewhere need a local processor offering comparable interchange-plus or subscription pricing, such as Helcim in Canada or Stripe and Square in the UK and EU, since Stax's underwriting and card-network relationships are US-based.
