As a SaaS platform evaluating interchange pass-through pricing, you’re likely already thinking beyond basic payment acceptance.

You want to understand what you’re really paying, where your margins come from, and how to turn payments into a scalable part of your business rather than just an administrative cost center.

But getting clarity on pricing isn’t always easy. Many SaaS platforms run into the same frustrations with their integrated payments:

• Flat-rate pricing masks your true unit economics. You’re paying the same 2.9% + $0.30 regardless of whether your merchant runs a $5 coffee or a $5,000 B2B invoice. This lack of transparency makes it impossible to see where you’re overpaying.
• Margins are difficult to optimize. Without visibility into the processor’s markup, it’s challenging to design a pricing model for your integrated payments that scales alongside your business.
• Limited flexibility prevents growth. Most third-party providers don’t give you the control to tailor pricing to different merchant segments or adjust rates as your strategy evolves.

Interchange pass-through pricing offers a more transparent approach by separating the underlying costs from the provider’s markup. However, it also introduces a level of detail that many SaaS founders find overwhelming. In this guide, we’ll break down exactly how this model works and how it compares to flat-rate pricing so you can decide which path is right for your platform.

In this article:

• What is interchange pass-through pricing, and how does it work?
• What to consider when comparing pass-through vs. flat-rate pricing
• Why does it make sense to partner with Fiska?

Fiska is an embedded payments solution that helps SaaS platforms monetize payments with transparent interchange-based pricing. Book a no-obligation call with our experts to see how we can help you turn payments into a revenue driver.

What is interchange pass-through pricing, and how does it work?

To understand pass-through pricing, you first have to understand interchange.

Interchange is the baseline fee charged on every single card transaction. It’s set by the credit card networks (Visa, Mastercard, and Discover) and is paid directly to the bank that issued the customer’s card.

Source: Matt Brown

The absolute dollar amount of this fee isn’t static. It fluctuates based on several variables, including the type of card used (debit vs. rewards credit), the environment (in-person vs. online), and the specific industry of the merchant.

In a blended or flat-rate model, these costs are hidden inside a single rate like 2.9% + $0.30. The processor averages these costs across their entire portfolio and builds in a high enough margin to cover the most expensive rewards cards. You pay the same fixed price even when the actual underlying cost is much lower.

Interchange pass-through pricing, often called interchange-plus, changes this by itemizing every component of the fee. It’s made up of three distinct parts:

• The interchange fee: This is the wholesale cost paid to the issuing bank. For an omnichannel payment solution, the interchange rates might be 1.18% for a card-present credit card transaction at a grocery store, or roughly 1.80% for an online rewards card.
• Assessment fees: These are smaller fees paid directly to the card networks (Visa/Mastercard/American Express) for maintaining their systems, usually around 0.13% to 0.15%.
• The processor’s markup: This is the only part the payment provider keeps. It’s usually a small flat fee per transaction plus a small percentage.

Source: Matt Brown

A comparison of costs: pass-through vs. flat-rate

Let’s look at a $100 online transaction using a standard Visa rewards card.

Fee component	Interchange pass-through	Flat-rate (Stripe model)
Interchange fee (1.80% + $0.10)	$1.90	Included in rate
Assessment fee (0.13%)	$0.13	Included in rate
Processor markup (0.30% + $0.10)	$0.40	$3.20 (total bundled fee)
Total fee to merchant	$2.43	$3.20

In this scenario, pass-through pricing is significantly cheaper because you aren’t paying for the “buffer” that flat-rate providers build into their fees to ensure they never lose money on high-cost cards.

What to consider when comparing pass-through vs. flat-rate pricing

Choosing between these models isn’t just about finding the lowest number. The right fit depends on your business stage and the specific card mix your merchants handle.

Flat-rate models offer early simplicity for low-volume platforms. However, as you scale, that same simplicity becomes a liability that drains your margins.

Interchange pass-through might make more sense if your merchants process high volumes, rely heavily on low-cost debit cards, or operate across multiple omnichannel sales channels.

How much support capacity you have to explain more complex balance statements to customers

Flat-rate pricing is designed for ease. It is attractive for early-stage merchant onboarding because it’s easy to explain and even easier to bill.

Merchants see one rate, they know exactly what will be deducted from each sale, and they don’t have to worry about the “alphabet soup” of interchange categories.

Interchange pass-through pricing, while more transparent, can be harder for small merchants to interpret. They’ll see itemized fees for every network and card type.

You have to decide if your primary goal is minimizing support questions or enabling your merchants to see exactly what they’re paying for. Most established, high-volume merchants will happily trade a slightly more complex statement for the significant cost savings pass-through pricing provides.

Whether to lower prices for merchants or bundle payments into a high-value offering

The model you choose determines how you earn from payments. Flat-rate pricing often locks you into a static margin. If you use Stripe Connect and want to share revenue, you are essentially adding a markup on top of an already high 2.9% rate, which can quickly make your platform too expensive for your merchants.

In contrast, interchange-plus allows for dynamic revenue strategies. You can set a fixed markup above interchange, ensuring that you remain competitive while scaling your revenue alongside your merchants’ growth.

This model allows you to capitalize on lower-cost transactions (like debit cards) where your margin will be higher than it would be under a blended rate.

Read more: Alternative models to Stripe Connect for SaaS platforms

Why does it make sense to partner with Fiska?

Fiska works only with software companies to replace high, fixed fees with a model where you keep more money on every sale. We built our platform specifically for founders who are tired of losing profit to processors that hide their real costs behind a single, expensive rate.

Here are three reasons why SaaS companies choose our ISV payment partner model:

1. Launch integrated payments with a unified API and control your pricing

Fiska enables you to embed payments directly into your platform via a modern unified API. This covers in-person, online, and mobile payments across the U.S. and Canada, removing technical friction and making transactions effortless for your merchants. With Fiska:

• Set your own margins above interchange. Because our cost base is interchange, you can add your own markup while remaining more competitive than flat-rate providers.
• Scale revenue alongside volume. As your merchants grow, your revenue grows. You get to keep the margin that traditional processors usually hide in their blended rates.
• Maintain strategic flexibility. You choose how to package payments. You can bundle them into your SaaS subscription, offer them as a standalone feature, or vary pricing by vertical or customer segment.

2. Deliver a fully branded, customizable experience

When you can’t white-label your payment solution, your platform stops feeling like a unified operating system and starts feeling like a thin UI layer over another company’s tools.

If a merchant’s customer sees Stripe’s logo and branding at checkout instead of yours, it breaks the user experience and signals that you aren’t actually handling the core transaction.

This creates immediate friction: customers get confused by who they are paying, merchants wonder why they are paying for your software when they are essentially using a third-party processor, and you lose the chance to build long-term brand equity in your most critical workflow.

With Fiska:

• You own the end-to-end user experience. Customize the onboarding flow and checkout screens so they align perfectly with your brand design.
• Build trust with consistent branding. Keep customers inside your ecosystem from the moment they sign up until the moment they receive their receipt.
• Minimize signup drop-off. By streamlining the workflow and removing third-party redirects, you improve conversion rates for your merchants.

3. Get strategic support: we act as your fractional head of payments

Most platforms don’t have the budget to hire a dedicated payments team. Fiska fills that gap by acting as your expert consultant on everything from interchange optimization to monetization strategy.

• Reach us on your terms. Forget about ticket-based systems that take days to respond. You can reach our dedicated team via Slack, phone, or email.
• Access Level 1 and 2 support. We reduce your team’s workload by providing direct technical assistance. If you’re still unable to help your merchants, we can step in and interact with them directly in certain circumstances. 
• Navigate compliance with ease. We handle the complex PCI compliance certifications and risk management so your team can stay focused on your core software.

Drive growth with transparent, scalable payments powered by Fiska

Interchange pass-through pricing gives you the control to manage costs, optimize margins, and scale revenue as your merchants grow.

Fiska helps you put that model into practice without adding complexity. You get the flexibility to set your own pricing, the infrastructure to support it, and the strategic guidance to keep improving over time.

If you’re ready to turn payments into a scalable, revenue-generating part of your platform, Fiska gives you the foundation to do so.

Book a no-obligation call with our payments experts to discover how Fiska can improve your payment experience.

FAQ: Interchange pass-through pricing

How is interchange pass-through pricing different from flat-rate pricing?

Flat-rate pricing combines interchange fees, network costs, and the payment processor’s markup into one fixed rate. While this can simplify billing for a small business, it often increases overall payment processing costs and hides the true transaction fees.

Interchange pass-through pricing, also known as interchange plus pricing, separates each cost. This includes fees set by the card-issuing bank, scheme fees, and the processor’s margin. This gives merchants full visibility into credit card processing fees and helps them understand how different payment methods and transaction types affect their bottom line.

Is interchange pass-through pricing more cost-effective?

In most cases, yes. Because you pay the actual rates set by card issuers and the acquiring bank, plus a transparent markup, this model is usually more cost-effective than tiered pricing or flat-rate models.

Costs can vary depending on transaction amount, transaction volumes, and the type of transaction, such as card-not-present transactions or debit card transactions. Over time, this structure often leads to lower interchange fees and reduced overall transaction costs.

What factors affect interchange fees?

Interchange fees are influenced by several variables, including the type of card payments being processed, the cardholder’s bank, and the level of risk involved. For example, card-not-present transactions typically carry a higher risk of fraud, which can increase fees.

Other factors include whether a transaction is classified as qualified, mid-qualified, or non-qualified, as well as the industry, payment method, and fraud prevention measures in place.

Who should use interchange pass-through pricing?

This model is ideal for SaaS platforms, marketplaces, and merchants with consistent or growing transaction volumes. If you are moving beyond basic payment service providers and want more control over your payment processing costs, it becomes a strong option.

Businesses with a merchant account and more complex payment processing needs benefit most, especially those working with multiple service providers or offering a wide range of payment methods.

How does interchange pass-through pricing impact cash flow?

Because pricing is based on the true cost of each transaction, fees may vary slightly month to month. However, this transparency allows businesses to better forecast and manage cash flow over time.

By reducing hidden markups and avoiding inflated flat rates, merchants can improve margins and make more informed decisions about their payment processor and overall payment strategy.