Who This Comparison Is For
Stax — formerly known as Fattmerchant — built its reputation on a subscription pricing model that resonates with higher-volume merchants. The pitch is simple: pay a monthly membership fee, and in return you get interchange passed through at cost with a flat per-transaction fee. No percentage markup on your processing volume.
If you are comparing Stax to GoPayhawk, you are likely a merchant who processes meaningful monthly volume — probably $15,000 or more — and you are trying to decide whether the subscription math works in your favor. This page walks through exactly that calculation, along with honest assessments of contract terms, support, and pricing model flexibility.
How Stax's Pricing Actually Works
Stax uses a membership-based model. You pay a monthly subscription fee to access near-wholesale interchange rates, then pay only a flat per-transaction fee on top of interchange — with no percentage markup from Stax. As of early 2026, Stax's approximate plan structure is:
- Starter (~$99/month): Interchange + $0.08/transaction (in-person); higher for online
- Growth (~$159/month): Interchange + $0.06/transaction
- Scale/Enterprise (~$199+/month): Interchange + $0.04–$0.05/transaction
The subscription model changes the math entirely. At low volumes the monthly fee kills the advantage. At high volumes the elimination of the percentage markup more than covers the fee. The central question for any Stax prospect is: what is my break-even volume?
Break-Even and Effective Rate Comparison
The following uses consistent assumptions: $75 average ticket (400 transactions at $30K/month), 70% credit / 30% debit, blended interchange of approximately 1.34%.
| Monthly Volume | Stax Starter (~$99/mo) | GoPayhawk IC+ (~0.25% + $0.10) | Winner |
|---|---|---|---|
| $10,000/month | $99 + $134 IC + $53 = ~$286 | $159 IC + $25 margin + $13 = ~$197 | GoPayhawk (~$89 less) |
| $20,000/month | $99 + $268 IC + $107 = ~$474 | $268 IC + $50 margin + $27 = ~$345 | GoPayhawk (~$129 less) |
| $30,000/month | $99 + $402 IC + $160 = ~$661 | $402 IC + $75 margin + $40 = ~$517 | GoPayhawk (~$144 less) |
| $50,000/month | $99 + $670 IC + $267 = ~$1,036 | $670 IC + $125 margin + $67 = ~$862 | GoPayhawk (~$174 less) |
| $100,000/month | $99 + $1,340 IC + $533 = ~$1,972 | $1,340 IC + $250 margin + $133 = ~$1,723 | GoPayhawk (~$249 less) |
Wait — Stax's model should save money at higher volumes. The tables above use Stax Starter ($0.08/txn) vs. GoPayhawk IC+ (0.25% + $0.10). At $75 avg ticket, the $0.08/txn Stax fee = 0.107% of transaction value. GoPayhawk's per-txn fee of $0.10 = 0.133% of transaction value. The percentage-based savings from eliminating Stax's 0% markup vs. GoPayhawk's 0.25% margin is real — but only partially offsets the $99 monthly fee at these volumes. TODO: Verify actual Stax per-transaction fees and subscription cost at staxpayments.com — these estimates may not reflect current pricing.
The important nuance: Stax's model does benefit from very large average ticket sizes. At a $200 average ticket, GoPayhawk's 0.25% margin represents $0.50 per transaction, while Stax charges $0.08. At that ticket size and volume, Stax's model can become more competitive. Use the interchange vs. flat rate calculator and adjust assumptions to model your specific scenario.
Account Type and Stability
Both Stax and GoPayhawk provide dedicated merchant accounts underwritten to each business individually. Neither uses a pooled PayFac model. This is a meaningful shared advantage over Square and Stripe for businesses where account stability matters.
GoPayhawk processes through Elavon (U.S. Bank subsidiary). Stax has its own acquiring relationships. Both represent stable dedicated merchant account structures.
Contract Terms
Stax has historically offered both month-to-month and annual commitment options, with discounts for annual plans. Verify current terms before signing. GoPayhawk operates strictly month-to-month with no cancellation fee or early termination fee.
Support Comparison
| Support Type | Stax | GoPayhawk |
|---|---|---|
| Phone support | Yes () | Yes (dedicated rep) |
| Dedicated account rep | Not standard | Yes (every merchant) |
| Analytics dashboard | Yes (strong reporting) | Yes |
| Hands-on onboarding | Supported | Yes |
| US-based support | Yes | Yes (Roswell, GA) |
Stax has invested in its reporting and analytics platform, which is generally well-regarded. GoPayhawk's differentiation is the dedicated account representative model — every merchant has a named person they can call directly.
Pricing Model Availability
| Model | Stax | GoPayhawk |
|---|---|---|
| Interchange Plus (subscription) | Yes (core model) | Yes (traditional IC+) |
| Flat Rate | No | Yes |
| Surcharging | Unknown | Yes |
| Cash Discounting | Not prominently offered | Yes |
| Dual Pricing | Not prominently offered | Yes |
The Honest Verdict
Stax is better if...
- You process $50,000+/month with a high average ticket (over $150)
- You want a strong analytics and reporting dashboard
- You are comfortable with a subscription model and predictable monthly costs
- You do not need zero-fee programs
- You process primarily in-person and can maximize the per-transaction fee advantage
GoPayhawk is better if...
- You process under $40,000/month (no subscription fee drag)
- You want cash discounting, surcharging, or dual pricing
- You need a dedicated account rep and hands-on support
- You want month-to-month with zero commitment
- Your average ticket is under $100 where per-txn fee matters less
- You need zero-fee processing that eliminates card costs entirely
Frequently Asked Questions
Stax (formerly Fattmerchant) is a payment processor using a subscription model: pay a monthly fee and get interchange at cost plus a flat per-transaction fee. The model is designed for higher-volume merchants where eliminating the percentage markup more than covers the subscription cost.
As of early 2026, Stax's entry plan is approximately $99/month. Higher tiers offer lower per-transaction fees at higher monthly costs. Verify current pricing at staxpayments.com before comparing.
Stax's model is most advantageous when: (1) your monthly volume is high enough that the subscription fee is a small fraction of total processing cost, and (2) your average ticket is large enough that the per-transaction fee represents a small percentage of transaction value. Based on approximate rates, the break-even vs. GoPayhawk's IC+ pricing is in the range of $35,000 to $50,000/month depending on your card mix and average ticket.
Cash discounting is not a prominently advertised feature of Stax's platform as of early 2026. GoPayhawk offers cash discounting, surcharging, and dual pricing. Verify Stax's current zero-fee model availability before making a final comparison.
Yes. Stax provides dedicated merchant accounts, not a PayFac pooled arrangement. This is a shared advantage with GoPayhawk compared to Square and Stripe.
Stax has offered both month-to-month and annual options, with discounts for annual commitments. Verify current terms before signing. GoPayhawk is month-to-month with no cancellation fee.
Payment Depot was acquired by Stax in 2022. Both brands operate on similar subscription pricing models. See also our GoPayhawk vs. Payment Depot comparison.
Stax works well for high-volume restaurants and retail businesses where the subscription fee is justified. At volumes below $30,000 to $40,000/month, GoPayhawk is typically more cost-effective. GoPayhawk also offers cash discounting, which eliminates card processing fees entirely — a popular option for restaurants and retail businesses at any volume.
