CardX Review

CardX is a US credit card surcharging service owned by Stax Payments. Jonathan Razi founded it in 2013, and Stax bought it in November 2021, when CardX had about 2,600 customers. It still trades as 'CardX by Stax' from Chicago. The idea is simple: when a customer pays by credit card, CardX adds a 3% surcharge that covers your processing cost, so on a $100 sale the customer pays $103 and you receive $100. Card-brand rules do not allow surcharges on debit cards, so CardX detects them, charges the customer nothing extra and charges you 1.25% + $0.25 instead. On top of that you pay a subscription that starts at $99 a month. As of September 2026 CardX publishes all of this on its pricing page, promises next-business-day funding and charges no cancellation fee; either side can end the service on 30 days' notice. CardX handles card-brand registration, signage, disclosures and receipts, but its terms leave legal responsibility for surcharging compliance with you. It does not serve businesses in Connecticut or Massachusetts. It says it serves Maine under unpublished terms, although Maine's statute says sellers may not surcharge card payments, and New York and Colorado law add extra conditions. CardX has an A+ rating from the BBB with no complaints, but almost no public customer reviews anywhere.

Estimated annual cost at three realistic processing volumes, using CardX’s published online rate plus monthly fees. Real costs vary with average transaction size, chargeback rate, and any negotiated terms.

What CardX is

CardX is a US company that lets businesses add a surcharge to credit card payments legally, so the customer who chooses a credit card pays the cost of accepting it. Jonathan Razi founded it in 2013 while studying law at Harvard, according to a 2018 Built In Chicago profile that CardX republishes on its blog, and the BBB lists the Chicago business as started on 16 December 2013. CardX says it was founded because new rules that year first let US businesses pass on the fee when customers choose credit cards, something universities and government had long been allowed to do. CardX grew by selling to businesses directly and by licensing its technology to processors, resellers and software companies. It also serves schools and government offices.

Stax Payments, the Orlando subscription-pricing processor formerly called Fattmerchant, announced its purchase of CardX on 30 November 2021. The announcement said CardX had 2,600 active customers, 'representing more than $1 billion in processing volume', that CardX would 'continue to operate as a stand-alone brand', and that Razi and CardX's chief operating officer would join Stax's leadership. CardX still runs from 401 N. Michigan Avenue in Chicago. As of September 2026 its site says it has more than 5,000 customers, that it has delivered $55 million in savings since 2023, and that more than 200 payment processors and ISOs use its technology. The site gives no dates for these figures. CardX's site also says that in 2022 it became the first surcharging service available in Canada. This review covers the US product.

Why we list CardX as an ISO

CardX does not hold the card-acceptance agreement itself. Its terms describe CardX as a licensed software service used alongside a separate merchant processing agreement with a card processor, and its website footer says Stax Payments is a registered partner/ISO of Elavon, a subsidiary of U.S. Bancorp. The pricing page notes that debit pricing 'varies among processor platforms', which indicates that not every CardX merchant runs on the same processor. We therefore list CardX as an ISO product, with the processor holding the merchant agreement. It is not a high-risk specialist.

How the money works: what the customer pays and what you pay

The surcharge and your cost are two different numbers, and it helps to keep them separate.

• Credit card sale: the customer pays the sale plus 3%. On a $100 sale they pay $103. CardX charges its credit discount rate on the transaction, and the surcharge covers it, so you receive $100. CardX calls this '0% net cost' and adds 'where eligible'.
• Debit or prepaid card sale: no surcharge is allowed. The customer pays $100 and you pay 1.25% + $0.25, so you receive $98.50. On some processor platforms commercial debit cards cost 2.91%, and key-entered debit on the CardX Terminal does not qualify for the 1.25% rate.
• Subscription: from $99 a month for the in-person plan, and from $99 a month for the in-office and online plan, as of September 2026.
• Refunds and chargebacks: CardX refunds the surcharge with the sale, pro-rated for partial refunds. Its terms say discount fees are charged on gross sales 'without reduction for refunds, returns, or chargebacks', so you keep paying the processing cost of a refunded sale without the surcharge to cover it. The per-transaction debit fee is also charged on each debit refund as well as each sale.
• Tips on paper: tips written on a paper receipt cannot be surcharged, but you pay the discount fee on them.
• Optional extras: ACH at 1% per transaction capped at $10, terminals priced per unit on Stax's equipment page, and a $19-a-month terminal protection plan.

As an illustration, take a business processing $20,000 a month, $14,000 on credit cards and $6,000 on debit cards in 120 debit transactions, with no refunds. Customers would pay $420 in surcharges, and the business would pay $99 in subscription plus $75 + $30 = $105 in debit fees: $204 a month, about 1% of volume. A business with more debit sales, smaller tickets or frequent refunds would pay a larger share. The figure also leaves out any processor fees, such as chargeback or PCI fees, that CardX does not publish.

The surcharging rules CardX works within

CardX's surcharging page summarises the card-brand rules it complies with: register with the card brands, post signs at the entrance and point of sale, keep the fee at or below 3% and make no profit from it, process the fee and the sale as one transaction, itemise the fee on the receipt and never surcharge debit cards. Its terms cap the surcharge at 'the lesser of 3% or Merchant's discount rate'. State law then adds its own limits. We checked the ones CardX names against the statutes, as of September 2026:

• Connecticut and Massachusetts: surcharges on credit card payments are banned (Conn. Gen. Stat. § 42-133ff; Mass. Gen. Laws ch. 140D, § 28A). Both still allow a discount for paying in cash. CardX does not serve either state, and its terms also exclude Puerto Rico.
• Maine: 9-A M.R.S. § 8-509 says a seller 'may not impose a surcharge' on a customer paying by credit or debit card, with an exception for government bodies; the statute adds that a discount from the regular price is not a surcharge. CardX nonetheless says it is available in Maine and that 'additional terms apply', which it does not publish. We could not find any public explanation of how the two fit together, so a Maine business should get CardX's written explanation of how its program complies before signing.
• New York: since 11 February 2024, General Business Law § 518 requires a business that surcharges to post the total credit card price, including the surcharge, and limits the surcharge to what the card company charges the business. CardX says additional terms apply in New York.
• Colorado: since July 2022, C.R.S. § 5-2-212 has allowed a surcharge of up to 2% of the sale or up to the merchant discount fee actually incurred, bans surcharges on debit cards and requires specific wording on signs. CardX's pricing page does not say how it applies these limits.

The card-brand rules may change too. In November 2025 Visa and Mastercard announced a revised settlement with US merchants that would loosen some acceptance and surcharging rules, and a federal judge in Brooklyn gave it preliminary approval on 9 June 2026. It had not received final approval as of September 2026, and some large merchants and retail trade groups have objected to it. Any change would come through CardX's program, but it is one reason to keep a 30-day exit.

Contract, funding and fund holds

CardX's Client Terms and Conditions were last updated on 11 April 2023. Either side can end them on 30 days' notice for any reason, and the pricing page says there are no cancellation fees. CardX can reprice on 30 days' notice, suspend the service without notice if you owe it money, and end the service immediately for a material breach. Funding is next business day. CardX's own terms contain no clause about reserves or holding funds. Settlement, reserves, chargebacks and processor fees sit in the separate merchant processing agreement, which CardX does not publish, so ask for it and read those clauses before signing. CardX's terms also say its liability is capped at what you paid it, and they require individual arbitration with JAMS in Chicago.

Compliance: what CardX does and what stays with you

Under its terms, CardX completes card-brand registrations, tells credit cards from debit cards, discloses the fee and its dollar amount on its payment pages and receipts, lets the customer cancel before paying, submits the fee and the sale as one transaction and refunds the fee with the sale. You remain responsible for signs at your entrance and till, verbal disclosure on phone orders, calling the charge a 'surcharge', and not surcharging tips on paper. The terms say in capitals that you have 'sole responsibility and liability' for complying with applicable laws, and they disclaim any guarantee that using CardX makes you compliant. That is standard for software vendors, but it sits uneasily with marketing that promises 'automated compliance'.

Advocacy and litigation

CardX has spent years in court on surcharging. It filed a friend-of-the-court brief in November 2016 in Expressions Hair Design v. Schneiderman. On 29 March 2017 the US Supreme Court held that New York's no-surcharge law, as applied to merchants who wanted to post one price and charge card users more, regulated speech rather than just prices, and it sent the case back to the appeals court to review the law under the First Amendment. In 2020 CardX sued the Kansas attorney general over the state's surcharge ban (CardX, LLC v. Schmidt, D. Kan. No. 20-2274). On 25 February 2021 the federal district court held that the ban, as applied to CardX's software, violated CardX's First Amendment rights; it granted a declaratory judgment but declined to issue an injunction. CardX was the plaintiff in that case. We found no lawsuit or regulatory action naming CardX as a defendant.

Reputation

As of September 2026, CardX's BBB profile (Cardx, LLC, Chicago) shows an A+ rating, no accreditation, no complaints and no customer reviews. Its Trustpilot page is unclaimed and has no reviews. We found no meaningful volume of merchant reviews elsewhere either, so there is little public evidence on support quality one way or the other. Reviews of Stax, the parent company, are a separate matter and are covered in our Stax review.

Who should use CardX

CardX fits a US business outside Connecticut and Massachusetts that takes a lot of credit card payments, sells at prices where a 3% card fee will not drive customers away, and wants a vendor to handle the card-brand side of surcharging. Trades, professional services, B2B suppliers and schools or public bodies are the obvious fits. It suits businesses less well when most customers pay by debit card, tickets are small, refunds are frequent, or the business is in Maine, New York or Colorado and does not want to work through the extra state rules. Before signing, get the merchant processing agreement and the state-specific terms in writing.