Open Gateway Billing: A CFO’s Strategy to Cut SaaS Fees

Payment processing is one of SaaS's largest hidden costs

Most B2B SaaS companies accept credit cards and ACH as the default payment methods. As transaction volumes grow, the associated processing fees scale with them. What begins as a minor line item can quickly become a top 5 expense category.

The challenge is compounded by bundled agreements. Many SaaS businesses are locked into payment gateways that offer limited flexibility. These bundled offerings may simplify initial setup but rarely support cost optimization as the business scales.

An open gateway model changes that. It gives your team the ability to route payments through different processors, compare rates, and switch based on performance or cost—without rebuilding your billing system.

Interchange fees are non-negotiable, but margin isn’t

Interchange fees are set by card networks and cannot be avoided. But the markup your business pays on top of those fees varies significantly between payment gateways. That markup includes gateway fees, per-transaction surcharges, and other line items that drive up your effective rate.

Most SaaS companies pay between 2.8% to 3.4% per transaction. By switching to an open gateway model, many reduce that to 2.2% or less, depending on payment mix and volume. Across millions in annual recurring revenue, that can cut payment processing costs by up to 40%.

Open gateway models increase flexibility

An open payment gateway model means your subscription billing platform is not tied to a single processor. Instead of relying on a bundled solution, you can connect to multiple gateways—such as Authorize.net, NMI, or Stripe—and choose the one best suited for each use case.

This structure allows you to:

• Run A/B tests on processing costs
  
• Route transactions based on geography or currency
  
• Separate domestic and international payments
  
• Avoid vendor lock-in
  
• Negotiate better rates by showing competitive benchmarks
  

In high-growth SaaS environments, even 0.1% improvement in effective processing rate delivers measurable bottom-line results.

Reduce churn from failed or blocked transactions

Payment gateway flexibility is not just about savings. It also improves reliability.

Some gateways are better than others at handling specific card types or international transactions. If your primary gateway declines a legitimate payment, that can trigger involuntary churn.

By adding fallback gateways or re-routing based on retry logic, your finance team can increase successful collection rates and reduce failed payments.

Gateway negotiations become data-driven

Negotiating better payment terms requires leverage. When your billing platform only works with one gateway, you lose that leverage.

With an open gateway setup, you can benchmark gateway performance across multiple vendors. That includes:

• Approval rates by card type
  
• Fees by region or transaction volume
  
• Time to payout
  
• Integration reliability
  

This data makes it easier to push for lower rates or volume-based discounts from existing processors.

If your SaaS platform is processing high volumes of recurring transactions, using that data to renegotiate can save tens of thousands annually. Learn how ChargeOver helps finance leads centralize gateway reporting.

Switching gateways shouldn’t mean rebuilding billing

The cost of switching gateways used to involve development hours, integration downtime, and risk. But modern billing systems decouple your internal workflows from the payment processor.

Platforms like ChargeOver allow you to connect new gateways with no disruption to:

• Subscription logic
  
• Dunning workflows
  
• Customer notifications
  
• Reporting dashboards
  

This is especially important when onboarding a new market or launching a new pricing model. You can test payments with a new gateway without touching your core billing logic.

Avoid revenue leakage during platform migrations

For finance teams moving off legacy processors, open gateway billing systems reduce revenue risk. You can keep your existing recurring billing logic intact while gradually shifting payment methods or testing lower-cost processors.

This phased migration reduces the risk of failed renewals, missed invoices, or duplicate charges.

As your SaaS business grows, being able to control who processes payments—and at what cost—becomes a strategic advantage.