How U.S. SaaS Companies Handle Payments From Your Customers

What SaaS payment processing does and why it matters to your business

SaaS payment processors let you collect money from customers without building your own payment system from scratch. They sit between your software and your customer's bank account, handling the technical work of taking a card number, checking it's valid, moving the money to your account, and keeping everything secure enough that you don't get sued or shut down.

The reason you need one is simple: accepting payments yourself means storing credit card data, which triggers federal compliance rules (PCI-DSS) that are expensive and risky to manage alone. A SaaS payment processor takes that burden. You send them a customer's payment details through their system, they handle the compliance, and you get the money in your bank account a few days later, minus their fee.

Most U.S. SaaS companies use one of a handful of processors because the market is concentrated. Stripe, Square, PayPal, and Braintree handle the majority of online transactions. Each has different pricing, different features, and different rules about what kinds of businesses they'll work with.

Key Takeaways

• SaaS payment processors collect money from your customers and deposit it into your bank account, handling security and compliance so you don't have to.
• Stripe, Square, PayPal, and Braintree are the four largest processors in the U.S., and each charges different fees based on transaction volume and payment method.
• Fees typically run 2.2% to 3.5% of each transaction plus a per-transaction charge, but volume discounts and custom rates are common for larger businesses.
• Payment processors hold money in reserve (called a "reserve" or "rolling reserve") for 7 to 180 days to cover chargebacks and refunds, which affects your cash flow.
• Choosing a processor depends on your industry, transaction volume, international needs, and whether you need invoicing, subscription billing, or marketplace features built in.

How the money moves from customer to your bank account

When a customer enters their card number in your software, that data goes to your payment processor's servers, not to you. The processor checks with the customer's bank to confirm the card is real and has enough money. If the bank says yes, the processor holds the money temporarily and sends you a confirmation that the charge went through.

The processor then batches all your transactions together and sends them to the banking network (Visa, Mastercard, American Express, or ACH for bank transfers). The networks move the money from your customers' banks to your processor's bank account. The processor takes their fee and deposits the rest into your business bank account, usually within one to three business days.

This is why you see a delay between when a customer pays and when the money shows up in your account. The processor is not holding it to make money off the float—they're waiting for the banks to confirm the transfer actually happened and for any chargebacks to surface. If a customer disputes the charge within 180 days, the processor can pull the money back out of your account to cover it.

The four largest U.S. processors and what sets them apart

Stripe is the most popular for SaaS companies because it was built for software from the start. Their API is clean, their documentation is thorough, and they offer subscription billing, invoicing, and marketplace features without you having to build them yourself. Stripe charges 2.2% plus $0.30 per card transaction, or 3.5% plus $0.30 for international cards. They hold a rolling reserve of 1% of your volume for up to 120 days.

Square started in physical retail but now handles online payments too. They're simpler than Stripe—fewer features, easier to set up, but less customizable. Square charges 2.6% plus $0.30 per online transaction. They don't hold a reserve for most businesses, which means your cash flow is faster. Square is a better fit if you don't need complex subscription logic or marketplace tools.

PayPal is the oldest and most recognizable. Many customers trust the PayPal name and will pay through it even if they wouldn't enter their card directly. PayPal charges 2.2% plus $0.30 per transaction for standard payments, or 3.49% plus $0.49 for PayPal Credit. They hold a reserve that varies by business type and history, sometimes 7 days, sometimes 180 days. PayPal's integration is clunkier than Stripe's, but they have the largest customer base.

Braintree (owned by PayPal) sits between Stripe and PayPal in complexity. It's built for larger transactions and marketplace businesses. Braintree doesn't publish standard rates—you have to call for a quote. They hold a reserve based on your chargeback history and business type. Braintree is most common in fintech and high-value SaaS.

How fees work and what they cost you

Every processor charges a percentage of the transaction plus a flat per-transaction fee. For a $100 charge on Stripe, you pay $2.20 plus $0.30, leaving you $97.50. For a $10 charge, you pay $0.22 plus $0.30, leaving you $9.48. This is why small transactions hurt: the flat fee is the same whether the sale is $10 or $1,000.

Most processors also charge different rates depending on how the customer pays. Card-present (swiped in person) is cheaper than card-not-present (online). Debit cards are cheaper than credit cards. ACH bank transfers are cheaper than cards. International cards cost more. Some processors charge monthly minimums or monthly fees for access to features like invoicing or recurring billing.

Volume discounts are real but not automatic. If you process more than $10,000 per month, you can usually negotiate a lower rate. At $50,000 per month, you can negotiate significantly. At $500,000 per month, you can get custom pricing. The processor won't offer this unless you ask, and you usually have to be willing to switch to get their attention.

Hidden fees exist. Some processors charge for chargebacks ($15 to $100 per dispute), refunds (sometimes free, sometimes $0.25 to $1.00), failed payment retries, or accessing your data through their API. Read the pricing page carefully and ask about these before you sign up.

Reserves and how they affect your cash flow

A reserve is money the processor holds back from your payouts to cover chargebacks and refunds. If a customer disputes a charge or you issue a refund, the processor pulls the money from this reserve instead of from your bank account. Once the reserve period ends, they release it to you.

Reserves come in two forms. A rolling reserve holds back a percentage of each day's transactions for a set number of days. Stripe holds 1% for 120 days, meaning if you process $10,000 today, they hold back $100 and release it 120 days from now. A fixed reserve is a lump sum held upfront—some processors require $5,000 to $50,000 in reserve before you can process any payments.

This matters because it changes when you actually have access to your money. If you process $100,000 per month and Stripe holds 1% for 120 days, you have roughly $3,300 locked up at any given time. For a small business, that's real cash you can't use to pay your team or buy inventory. Larger businesses often negotiate shorter reserves or no reserve at all.

What to consider when choosing a processor

Start with your industry. Some processors won't work with certain businesses—adult content, gambling, high-risk categories like cryptocurrency or travel. If you're in one of these, your options narrow quickly. Stripe and PayPal both have published lists of restricted businesses.

Next, think about your transaction volume and growth. If you're processing $1,000 per month, the difference between Stripe and Square is $3 per month. If you're processing $100,000 per month, it's $300. At that scale, it's worth calling for a custom rate. If you expect to grow fast, pick a processor that scales with you—Stripe and Braintree are built for this, Square less so.

Consider what features you need built in. If you bill customers monthly, you need subscription management. If you're a marketplace connecting buyers and sellers, you need split payments and seller payouts. If you invoice customers, you need invoicing tools. Stripe includes most of these. Square and PayPal have them but with more friction. Braintree has them but requires more custom code.

Finally, think about international payments. If you sell to customers outside the U.S., you need a processor that handles multiple currencies and local payment methods. Stripe supports 135+ countries and 135+ currencies. PayPal supports most countries but with higher fees. Square is U.S.-focused. Braintree is in between.

How to switch processors without losing money or transactions

Switching is possible but requires planning. You can't just flip a switch—you have to update your code to point to the new processor's API, test it thoroughly, and coordinate the cutover so no transactions fall through the cracks.

The safest approach is to run both processors in parallel for a week or two. Send half your transactions to the old processor and half to the new one. Once you're confident the new one is working, switch everything over. This costs a little extra in fees but eliminates the risk of downtime.

Before you switch, make sure you understand what happens to your reserve. If your old processor is holding $5,000, they won't release it until the reserve period ends, even after you stop processing with them. Plan for this cash flow gap. Also check whether your old processor charges an early termination fee—most don't, but some do.

Frequently Asked Questions

Can I use multiple payment processors at the same time?

Yes. Many SaaS companies use Stripe for card payments and PayPal for PayPal wallet payments, or Stripe for U.S. customers and a local processor for international ones. This spreads your risk and can lower your overall fees if you negotiate volume discounts with each. The downside is more complex code and more vendor relationships to manage.

What happens if a customer disputes a charge?

The customer contacts their bank and claims they didn't authorize the charge or didn't receive what they paid for. The bank pulls the money back from your processor's account. Your processor then pulls it from your reserve or from your bank account if the reserve is empty. You can dispute the chargeback by providing proof the customer authorized the charge and received the product, but the burden is on you to prove it.

Do I have to use the processor's invoicing tool, or can I use my own?

You can use your own invoicing software and still use the processor for payments. Many SaaS companies use Stripe for payments and Wave or FreshBooks for invoicing. The processor only needs to know the customer's payment details and the amount—they don't care where the invoice came from. This gives you more flexibility but means you're managing two systems instead of one.

What's the difference between a payment processor and a payment gateway?

A payment processor handles the money—they move it from the customer's bank to yours and manage the reserve. A payment gateway is the software that collects the payment details and sends them to the processor. Stripe is both. Some companies use a gateway like Authorize.Net and a separate processor like First Data. For most SaaS companies, using one company that does both (Stripe, Square, PayPal) is simpler.

Can I negotiate my fees if I'm a small business?

Not usually until you hit $10,000 per month in volume. Below that, you're paying the published rate. Once you're at $50,000 per month, you have real leverage. Call the processor's sales team, tell them your volume, and ask what they can do. Be prepared to switch if they won't budge—that's the only reason they'll negotiate.