SaaS payment processing: what to look for in a provider

Key takeaways

• SaaS payment processing deals with the billing demands that are unique to subscription businesses, from recurring charges and plan changes to failed payment retries.

• The right processor should support multi-currency payments, local payment methods, automated billing, and global tax compliance as you scale.

• Airwallex lets you accept payments in 160+ methods across 180+ countries, with like-for-like settlement and Subscriptions to automate recurring billing.

If you're running a SaaS business, you don't process payments the way a typical online shop does. Subscriptions bring recurring charges, plan upgrades mid-cycle, failed payment retries, and multi-currency billing across different markets. You need a processor that's built for that level of complexity.

In this article, we'll walk through what SaaS payment processing involves, the challenges you'll run into, how to assess providers, and which platforms are worth looking at in the UK.

What is SaaS payment processing?

SaaS payment processing is the system that handles online transactions for subscription-based software businesses. Think of it this way: buying a cinema ticket is a one-time transaction. You pay, you get your ticket, and that's it. A gym membership works differently. You're billed monthly, you might upgrade to a premium tier, freeze your membership for a month, or cancel altogether. Each of those actions changes the billing. SaaS payment processing is built to handle that kind of complexity automatically.

This system covers everything from the payment gateway that captures your customer's card details to the transfer of funds into your account. But unlike standard eCommerce processing, it's designed to manage:

• Recurring billing on weekly, monthly, or annual cycles

• Tiered pricing plans with different feature sets

• Automated invoices and billing adjustments

• Local and global tax compliance, including VAT and GST calculations

SaaS payment processing also supports subscription management by letting customers pause, renew, cancel, upgrade, or downgrade their plans. Each of these actions affects billing and invoicing. For example, if a customer upgrades from a monthly Basic plan to an annual Pro plan mid-cycle, their charge needs to be prorated, their next billing date needs to be updated, and their invoice needs to be adjusted. A strong SaaS payment solution does all of that without manual work.

So, here's how the payment flow works behind the scenes.

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

These two terms get used interchangeably a lot, but they do different jobs. A payment gateway is the front door. It captures and encrypts your customer's payment details at checkout. Think of it like the card reader at a shop. The payment processor is the back-office engine that routes the transaction between your customer's bank and yours, like the bank transfer happening in the background.

For SaaS businesses, both need to support stored credentials and recurring triggers so you can charge customers automatically on their billing date. Some providers bundle the gateway and processor together. Others make you set up separate integrations.

How does SaaS payment processing work?

The underlying setup is the same as any payment processing system, but the workflow is different because of recurring billing. Here's the basic flow:

• Payment gateways accept and authorise the transaction.

• Payment processors communicate between bank accounts to confirm and transfer payments.

• Merchant accounts accept, hold, and disburse received funds.

What makes SaaS different is everything that happens around that flow. Instead of a one-off transaction, your system securely stores payment credentials, triggers charges on a schedule, handles plan changes mid-cycle by calculating proration automatically, and manages failed payment retries without you having to do anything.

Your SaaS payment processing system should record and organise customer details, including their subscription plan, payment history, and billing period. Then the processor triggers transactions and processes payments automatically at the right time.

Some providers go beyond payments. They also offer expense management tools and accounting integrations to cut down manual reconciliation, so you can spend more time growing your business and less time chasing spreadsheets.

That's the basic flow. But SaaS billing brings complications that standard payment processing doesn't need to deal with.

What challenges do SaaS businesses face with payment processing?

If you're managing subscriptions across different pricing tiers, billing cycles, and markets, you'll hit challenges that a standard payment processor isn't built to handle. Here are the main ones to plan for.

Managing complex billing models

Subscription pricing isn't simple. Most businesses offer packages with different features and pricing, plus trial periods, subscription discounts, custom enterprise deals, and more. Each customer's recurring billing can work differently and run on a different schedule.

Here's a concrete example: a customer upgrades from your Basic monthly plan to your Pro annual plan mid-cycle. Your billing system needs to prorate the charge for the remaining days on Basic, calculate the annual Pro fee, update the next billing date, and adjust the invoice, all automatically.

On top of tiered pricing, a lot of SaaS businesses now use usage-based or metered billing. If you charge per API call, per seat, or per transaction, your billing system needs to track usage in real time and calculate variable charges at the end of each period.

To avoid missed payments, make sure your provider offers retry features that automatically reattempt a failed payment based on the rules you set. Automated retries can save you a lot of time and effort when it comes to chasing customer payments.

Large enterprises might build a custom payment processing system in-house, but building and maintaining that kind of solution isn't cheap. Most SaaS companies get more value from established payment processing providers.

Recovering failed payments and reducing churn

Not all churn is voluntary. Some customers want to stay, but their payments fail because of an expired card, insufficient funds, or a temporary bank hold. That's involuntary churn, and it can quietly eat into your revenue if you're not set up for it.

Here's how it usually plays out: a customer's card expires. If you don't have automatic retries, you lose that subscription. If you do have a dunning workflow, the system retries the charge on the schedule you set, tells the customer to update their details, and gives them time to fix the issue before their access gets cut off.

The best SaaS payment processors include automatic card updaters that refresh expired card details with the customer's bank, along with retry logic that times reattempts for when they're most likely to work. Those features can make a big dent in involuntary churn without giving your support team more work.

Scaling across borders

Once you land your first customers in Germany or Japan, you'll need to accept local payment methods, show prices in local currencies, and deal with local tax rules. Every new market adds another layer of complexity.

In the Netherlands, for example, 70% of online transactions use iDEAL. If you don't offer it, you're probably losing Dutch customers at checkout. In Brazil, Pix has become the dominant payment method. In India, UPI processes billions of transactions monthly. A payment processor that only supports cards will hold back your growth in these markets.

Payment processors like Airwallex specialise in international transactions with features like:

• Global reach with payment acceptance supported in multiple currencies from over 180 countries.

• Diverse payment methods for customers to pay in local currencies via different payment methods like card and direct debit.

• Localised checkout experiences so customers see prices listed in their local currency.

• Multi-currency business accounts to manage multi-currency payment collection and reduce fees with like-for-like settlements.

• Competitive processing fees for international and domestic transactions to manage costs effectively.

These features help you improve conversion rates whilst keeping the cost of doing international business low.

Handling security and compliance

Making sure you have secure payment processing matters even more for recurring payments, because SaaS processors store and manage customer data over time.

When you're choosing a payment processor for your SaaS business, look at how it handles sensitive customer information and how it prevents fraud when accepting payments. Those measures help both you and your customers feel confident that data is safe.

Any business that processes, stores, or transmits card data must comply with PCI DSS. Key parts of that include building and maintaining a secure network, encrypting data in transmission and storage, and carrying out regular vulnerability assessments. For recurring card payments in the UK and EU, you'll also need to think about Strong Customer Authentication (SCA) requirements and 3D Secure (3DS) implementation.

We use machine learning to analyse transaction patterns and flag anomalies in real time, helping protect your business from fraudulent activity before it affects your revenue.

Managing tax compliance across markets

If you're selling to customers in 15 EU countries, you'll need to understand the EU VAT rules and you may need to register in each one, or use a provider that handles tax collection and remittance for you. The same goes for GST in Australia, sales tax in US states, and consumption taxes in other markets.

This is a pain point that catches a lot of scaling SaaS businesses off guard. Some payment providers have built-in tax calculation and compliance tools. Others make you connect separate tax software or manage it yourself. When you're comparing providers, think about how much of that burden you want to keep in-house versus outsource.

Reducing manual work with automation

Reconciliation can turn into a big administrative burden if you have a large number of customers.

Think about it like this. Some customers pay each month and get a month's service, which is simple enough. Others are annual customers who pay in advance and then receive service for 12 months. You can't recognise the revenue until that point. As your customer base grows, that complexity grows with it.

Automation is especially useful with the complicated subscription model SaaS companies depend on. As your business scales, accounting becomes a much bigger job. Solutions that integrate with accounting software like Xero, QuickBooks, or NetSuite can cut down manual reconciliation and keep your financial records consistent.

With those challenges in mind, here's what to look for when you're choosing a SaaS payment processor.

How to choose a SaaS payment processor

When you're comparing payment processing providers, focus on the capabilities that matter most for subscription businesses. The right choice depends on where you are now and where you're trying to go.

Key features to evaluate

• Payment method variety: Accept virtual cards, direct debit, and local payment methods in the countries you operate in, not just major card schemes.

• Multi-currency support and localisation: Accept international transfers and transactions, display prices in local currencies, and settle in multiple currencies to avoid unnecessary FX fees.

• Subscription management: Handle recurring payments, plan changes, upgrades, downgrades, and cancellations automatically.

• Billing and invoice automation: Generate invoices, manage proration, and handle complex billing scenarios without manual intervention.

• Fraud prevention: Automatically identify and block fraudulent transactions to protect your revenue.

• Revenue reporting and accounting integrations: Organise transaction data and sync with your accounting software for a complete picture of your financial position.

Matching your provider to your growth stage

Your needs will change depending on where you are in your growth journey.

Early-stage SaaS businesses (under £1 million ARR) often focus on simple setup and low fixed costs. You need something that works out of the box and doesn't require a dedicated payments team to run it.

Scaling SaaS businesses (£1–10 million ARR) usually need multi-currency support, strong subscription management, and the ability to accept local payment methods as they expand into new markets. Failed payment recovery also matters more as the customer base gets bigger.

Enterprise SaaS businesses (£10 million+ ARR) may need interchange-plus pricing for cost optimisation, payment orchestration across multiple providers, or custom integrations with existing financial systems.

When a Merchant of Record model makes sense

A Merchant of Record (MoR) is a provider that acts as the seller of record for your transactions. Think of it like hiring a property management company instead of being the landlord yourself. The MoR handles the admin, including tax compliance, refunds, and chargebacks, but you give up some control and margin.

With a standard payment processor, you're the merchant. That means you're responsible for VAT registration in each market, handling refunds, managing chargebacks, and staying compliant with local regulations. With an MoR, the provider takes on that liability.

An MoR model makes sense if you have a small team, sell in many tax jurisdictions, and want to avoid the complexity of VAT/GST registration across markets. It makes less sense if you want full control over pricing, customer relationships, and payment data, or if the margin hit doesn't fit your business model.

So, let's look at how some of the main UK-available providers compare against these criteria.

SaaS payment processing providers in the UK

The UK has several strong payment processors that cater to SaaS businesses. The best choice depends on your specific needs, including your markets, your billing complexity, and your growth plans.

The right choice depends on the payment methods you need, the markets you're targeting, and how much of your billing complexity you want your processor to take care of.

Simplify your SaaS payments with Airwallex

SaaS billing can get complicated, but the right payment processor should let you accept cross-border payments without all the manual work.

That includes tracking payments, reducing failed transactions, and improving cash flow. If you want to expand internationally, our payment solutions can help you reach new global audiences with a great user experience and lower costs.

Airwallex lets you accept multiple currencies and supports over 160 payment methods to improve the customer experience and support conversions. You can also cut FX conversion fees with like-for-like settlement, and get competitive processing fees for domestic and international transactions.

Frequently asked questions

How is SaaS payment processing different from standard payment processing?

SaaS payment processing is built for recurring transactions rather than one-time purchases. It manages stored payment credentials, triggers scheduled charges automatically, handles plan changes mid-cycle with proration, and retries failed payments without manual intervention.

Can I automate failed payment retries with SaaS processors?

Yes, most advanced platforms offer retry tools to automatically reattempt failed payments and reduce churn. The best processors also include automatic card updaters and dunning workflows to recover revenue from expired cards.

Do SaaS payment processors support international payments?

Yes, top providers like Airwallex support multiple currencies, local payment methods, and multi-currency pricing for global transactions. That lets customers pay in their preferred currency using their preferred payment method.

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

A payment gateway captures and encrypts payment details at checkout, while a payment processor routes the transaction between the customer's bank and yours. Many SaaS providers bundle both together, though some require separate integrations.

Is PCI DSS compliance required for SaaS businesses?

Yes, any SaaS business that processes card payments must meet PCI DSS requirements to protect customer data.

Sources and references

• https://www.americanexpress.com/en-us/newsroom/articles/amex-for-business/uk-smes-reveal-2023-international-expansion-plans-but-challe.html

• https://stripe.com/gb/use-cases/saas

• https://www.braintreepayments.com/features/recurring-billing

• https://www.braintreepayments.com/legal/acceptable-use-policy

• https://www.chargebee.com/saas-billing/

• https://gocardless.com/en-us/features/rpp-recurring-payments-page/

• https://gocardless.com/faq/merchants/international-payments/