Third-Party Payment Processors Explained: What They Are and When They Make Sense

What a Third-Party Payment Processor Actually Is

A third-party payment processor (sometimes called a payment aggregator or payment facilitator, or PayFac) lets your business accept card payments without opening your own merchant account with a bank. Instead, you operate as a sub-merchant under the processor's master merchant account. Stripe, Square, PayPal, and Braintree all work this way.

The processor has already done the underwriting work with an acquiring bank at the aggregate level. When you sign up, you are not being individually underwritten in the traditional sense. You are being screened against an automated risk model and then folded into a pool of thousands of other businesses sharing the same master account.

That structure is what makes onboarding fast. According to Stripe's own guide to payment facilitation, a PayFac model exists specifically to remove the weeks-long underwriting process a business would otherwise face with a traditional acquirer, replacing it with instant or near-instant approval ( Stripe, Payfacs: A guide to payment facilitation). The trade-off for that speed is that risk is now managed collectively, not individually, and that changes how the relationship behaves once your business is live.

How Third-Party Processing Actually Works

A transaction under a third-party processor moves through the same card network rails as any other payment, but your business is invisible to the acquiring bank as an individual entity. Here is the practical flow for an online order:

1. Your customer enters card details on your checkout page
2. The processor's gateway tokenizes the card and sends an authorization request
3. The request routes through the processor's own acquiring relationship (or a bank partner) to Visa or Mastercard
4. The card network routes to the customer's issuing bank for approval or decline
5. The response returns through the same chain, typically in under two seconds
6. At settlement, funds move into the processor's master account first
7. The processor allocates your share and deposits it into your bank account, usually on a one- to two-day rolling basis

Your business never touches an acquiring bank directly. Every step of that chain is between the processor and the network. That is convenient until step six or seven gets interrupted, which is the part most new merchants never think about until it happens to them.

Third-Party Processing vs a Direct Merchant Account

The pricing gap matters more than most first-time business owners expect. Flat-rate pricing bakes in a blended average across every card type your business will ever see, including premium rewards cards with the highest interchange. Businesses with a lot of debit card volume, common in restaurant and food delivery transactions, end up subsidizing the rewards-card transactions of other merchants inside the same blended rate ( Helcim, interchange-plus pricing guide).

Where Third-Party Processing Breaks Down for Growing Businesses

The failure mode is consistent enough that it has a name in the industry: the aggregator squeeze. It shows up in three specific ways.

Sudden Holds and Freezes

Because risk is monitored in aggregate, a legitimate volume spike, a shift in average transaction size, or a change in customer geography can trip an automated fraud model even when nothing fraudulent is happening. A subscription software company or a fast-growing food ordering platform is especially exposed here because both experience the exact volume and geography changes that automated risk models are built to flag. When that happens, processors can hold 5 to 10 percent of processing volume for 90 to 180 days with limited immediate explanation, a pattern well documented across payment industry forums and merchant advisory firms alike ( Swipesum, hidden processing fees and risk practices).

Pricing That Stops Making Sense at Volume

The crossover point where interchange-plus pricing from a direct acquirer becomes cheaper than a flat-rate aggregator is typically around $50,000 to $75,000 in monthly card volume. Below that, the simplicity of a flat rate usually wins. Above it, a business is paying a real premium every month for a convenience it no longer needs.

No Formal Recourse

Traditional acquirers operate under a contractual relationship with defined dispute and termination procedures. Aggregators can suspend accounts under their own terms of service, and because a business is one of thousands of sub-merchants, individual escalation paths are limited. This is not a flaw specific to any one processor. It is a structural consequence of the sub-merchant model itself.

Third-Party Processing for Marketplaces and Platforms

This is where the distinction between a payment processor and a payment facilitator actually matters in practice, and it is where most explainers stop short.

A payment facilitator (like Stripe Connect or Adyen for Platforms) is a specific type of third-party processor built for businesses that need to accept and then redistribute funds to other parties, such as a food ordering platform paying out restaurants, or a marketplace paying out individual sellers. The PayFac model lets the platform onboard its own sub-merchants under its umbrella, rather than sending every restaurant or seller to open an individual merchant account.

This is functionally different from a marketplace operating model, and the two get confused constantly. Visa's own risk guidance for payment facilitators and marketplaces draws the distinction on the basis of who holds settlement responsibility and who carries KYC obligations for the underlying sub-merchants ( Visa, Payment Facilitator and Marketplace Risk Guide). Get this wrong at the architecture stage and a platform can end up non-compliant with card network rules well before it has any indication something is wrong.

For classification purposes, marketplaces that handle multiple, unrelated lines of business are typically assigned MCC 5262, a category built specifically because a marketplace's transaction mix does not fit neatly under any single merchant category code. A restaurant delivery platform, by contrast, is usually classified under a single MCC tied to its dominant business line, which carries its own interchange and risk implications. See our guide to how payment processors classify your business vertical for the full mechanics.

How to Decide Between Third-Party and Direct Processing

Three questions determine the right answer for most businesses:

What is your monthly card volume? Below roughly $50,000 a month, the operational simplicity of a third-party processor usually outweighs the pricing gap. Above that, run the numbers on interchange-plus.

How predictable is your transaction pattern? A business with steady, familiar volume rarely trips risk models. A business with seasonal spikes, rapid growth, or high average transaction values is more exposed to holds under an aggregate risk model, regardless of how legitimate the business is.

Do you need to pay out other parties? If your business model involves splitting or forwarding funds to restaurants, sellers, or contractors, you need a payment facilitator architecture from day one, not a standard third-party processor bolted on later. Retrofitting this after launch is a much harder engineering and compliance problem than building it in from the start. Our marketplace founder's guide to payment processing covers this in more depth.

The Major Third-Party Processors Compared

Rates change often and vary by industry, so treat this as a starting point for a conversation with each provider rather than a final number.

Frequently Asked Questions