As a SaaS platform, you might be watching transactions flow through your platform without seeing a cent of that revenue. Your merchants might be dropping off at checkout because the payment experience feels disconnected from your product.

You know you need a new payment solution, but with so many payment APIs on the market, it can be hard to know where to start. Do you embed payments directly into your platform? Do you use a third-party checkout? And how do the available solutions actually differ from one another?

That’s what this article aims to explain. We’ll cover:

• Your payment options as a SaaS platform
• How payment APIs differ from one another
• Four top embedded payment APIs for SaaS
• Why SaaS platforms are choosing Fiska

Ready to improve your payment strategy and start earning more revenue? Book a call with our SaaS experts to learn how we can help.

Your payment options as a SaaS platform

How you handle payments shapes your product experience, your revenue, and how much operational responsibility you take on.

There are a few different options available to you:

Using a third-party platform: fastest setup, but has its limitations

The simplest starting point for payments is a third-party payment provider like Stripe. Setup is fast, and you can start accepting payments very quickly. If you’re reading this article, you’ve probably already experienced this option.

Pros

• Quick and easy to get started
• Low engineering work required
• Baseline compliance and fraud tools are built in, so you don’t have to manage the regulatory heavy lifting yourself

Cons

• You have to mark up the provider’s fixed fee, which can make you look expensive to your merchants
  Onboarding and branding are largely out of your hands, creating a disjointed experience that feels off-brand
• Decisions around disputes, chargebacks, and account reviews sit with the provider. That can mean held funds and very little flexibility when your merchants need support the most

Becoming a PayFac: highest degree of control but significant cost and operational overhead

Becoming a Payment Facilitator (PayFac) gives you the highest degree of control. In a PayFac setup, your platform operates under a master merchant ID, and your customers are onboarded as sub-merchants under your umbrella. You set the pricing they pay, while the acquiring and processing costs sit behind the scenes.

Onboarding is also faster since you’re not waiting on a bank to handle underwriting; however, this benefit is less impressive than it sounds. Even if you’re not a PayFac, onboarding with proper compliance checks can be completed in 24 to 48 hours.

Pros

• Full control over pricing and merchant onboarding
• Faster merchant onboarding since you handle underwriting yourself
• Higher revenue potential since you capture more of the payment economics
• More control over settlement and funding flows, so you can support complex needs like split payouts, surcharging, and tailored funding schedules for your platform and merchants

Cons

• Setup is very costly and complex, often taking months of specialist work before you can go live
• Fewer acquiring banks are willing to sponsor PayFacs, which limits your options and can slow down approval
• You take on direct responsibility for KYC and Know Your Business (KYB) compliance, chargebacks, fraud, and ongoing regulatory audits
• You need in-house payments and compliance expertise, including a named compliance officer, which adds ongoing operational and headcount cost

In recent years, a PayFac-as-a-Service model has become popular, letting you rent PayFac capabilities instead of building them yourself. You get some of the benefits without the full overhead, though you give up some control over onboarding and pricing in the process.

To go deeper on whether the PayFac model is the right fit for your business, see our guide to PayFac vs. ISO.

Embedded payments: embed payments directly into your product and earn a share of the revenue

Embedding payments directly into your platform means your merchants get paid without ever leaving your software. The experience feels like a natural part of your product rather than a bolt-on, and under the hood, your chosen provider’s APIs connect your platform to the payment network.

Pros

• You earn a share of every transaction processed on your platform, adding a revenue stream without raising software prices
• Payments become a reason to stay. When your software handles a merchant’s daily transactions, switching to a competitor means uprooting their payment setup, too, which raises the bar for churning significantly
• You can customize your merchant onboarding flow to match your product experience
• Your provider handles compliance requirements like KYC, PCI, and card network rules, reducing your burden significantly

Cons

• Some providers limit how much you can customize your onboarding flow, so it’s worth checking what’s actually possible before committing
• Pricing varies widely between providers, so make sure the take rate and fee structure work for your business before signing anything

Read more: Embedded payment solutions for SaaS/ISVs: How to choose one

 

How APIs differ: multi-channel vs omnichannel, and white-labeling

Now that you’ve seen the main ways platforms can offer payments, let’s zoom in on the APIs.

Most major payment APIs are stable, well-documented, and proven at scale, so reliability on its own usually is not the factor that separates them.

The real differences show up in how they support multiple channels and how much they unify the experience behind the scenes.

• A multi-channel API can cover online, in-store, mobile, and subscription payments, but each channel is typically handled as its own integration, with its own logic, reporting, and operational workflows. If you decide to add in-store payments later, for example, you’ll need to integrate that separately.
• An omnichannel API brings all those channels into a single, consistent flow. Payments, customer identities, and transaction data connect across touchpoints, so you can manage routing, reporting, and the customer experience in one place.

Omnichannel, on the other hand, is objectively almost always the better option than multi-channel because it removes fragmentation.

With a single flow and cross-channel tokenization, customers can reuse saved payment details across online, in-person, and phone payments. That reduces friction, improves completion rates, and increases the amount of revenue you can capture through your platform. It also keeps engineering simpler, since you maintain one integration and one set of reporting and reconciliation workflows.

For example, imagine you run a SaaS platform for HVAC companies. A technician finishes a job on-site and takes payment using a mobile card reader. A few days later, the same customer calls the office to pay for a follow-up service. With omnichannel payments, the office can pull up the customer’s saved payment token and process the charge in seconds. With a multi-channel setup, the in-field and back-office systems don’t share payment data, so the customer has to read out their card details again as if they’ve never paid before.

 

A comparison of four embedded payment APIs for SaaS platforms

If you want to maximize your revenue potential and maintain control over the payments experience without taking on the responsibility of handling compliance and risk management, an embedded payments model is a great option for most SaaS platforms.

The next decision is choosing the right provider. The difference between providers often comes down to how much you can white-label the experience, whether their API is truly omnichannel, how they structure pricing, and what kind of support you can expect when something goes wrong.

To help, we’ve compared four of the leading embedded payment APIs for SaaS platforms across each of those factors.

Here’s a quick comparison* at a glance (keep reading for more in-depth information).

Capability	Fiska	Stripe Connect	Worldpay for Platforms	Finix
Revenue share	Yes. True revenue share based on interchange plus margin split	Not true revenue share by default. Often ends up as fee on top unless you structure it separately	Possible, but depends on commercial setup. Often positioned more as configurable fee models	Often available depending on your agreement and fee setup
Pricing control	High. You set merchant pricing and split margin above underlying costs	Medium. You control what you charge, but pricing is anchored to Stripe’s baseline fees and merchant expectations	High. Configurable fees and more flexibility to define merchant pricing	High. Flexible fee settings, including transaction level pricing and volume based adjustments
Omnichannel API	Yes. Single omnichannel API with cross-channel tokenization	Not native out of the box. Usually needs Terminal plus shared tokenization	Not native by default. Best described as multi-channel with optional omnichannel capabilities	Multi-channel by default. True omnichannel depends on shared tokenization implementation
White-label	Yes. Full white-label across onboarding, checkout, receipts	Partial. Some customization, but full white-label often requires building your own onboarding UI	Partial. Branding is possible, but full white-label usually requires additional setup or custom UI	Strong. White-label options across onboarding, comms, reporting, and disputes
Support	Dedicated team via Slack, email, and calls. Level 2 merchant support available	Ticket-based support via Stripe	Email and ticket-based support	24/7 emergency support plus email and tickets

 

 Fiska: an embedded payment solution specifically made for SaaS platforms

As we’re writing this article, we thought we’d start with ourselves.

Fiska is an embedded payments partner that works exclusively with SaaS platforms. We started Fiska to help software companies implement payments in a way that would enable them to open a new revenue stream, offer a great merchant onboarding experience, and customize pricing for their customers.

When you choose Fiska, you get:

White-label payments for an experience that matches your software

Without the ability to white-label, payments will feel disconnected from your platform instead of appearing as a native feature of your software. When someone else’s logo appears at checkout, for example, you’re not positioning your platform as the sole system your customers rely on to run their business.

Fiska provides full white-label functionality across every checkout screen, receipt, and onboarding form. This means you can design your user experience and customize everything with your branding, not ours.

Read more: What to look for in a white-label payment solution

Support online, mobile, and in-person payments with a single integration

Omnichannel support makes payments more useful to customers and helps you win new verticals that rely on more than one payment channel.

With our single, omnichannel API, online, mobile, and in-person transactions are unified, meaning you only need to integrate once and don’t have to manage separate codebases or rebuild workflows when you expand into new channels.

We support platform-wide one-click payments with universal tokenization and enable you to set different rates depending on the channel. For example, you may want to set a higher rate for online transactions because interchange is higher than it is for in-person purchases.

Read more: Omnichannel payment solutions for SaaS: A guide

Turn payments into a revenue-driver with a fair revenue-share model

When you work with a third-party provider to accept payments, you work from a fixed public rate and have to mark that up to make a profit (this is known as a fee-on-top model). This puts you at risk of seeming too expensive to merchants, meaning you ultimately don’t take home any revenue from payments.

Instead of a fee-on-top model, we use a true revenue share model with an interchange cost basis. With this approach, you get to set the price your merchants see and split the margin that sits above interchange with us. This enables you to monetize payments while remaining competitive.

Support from people you know, through Slack, email, or calls: no support ticket queues

We understand how complicated payments can be, which is why we give all our payment clients access to a dedicated support team made up of experienced payments professionals. We’ll help you pick the right pricing model and guide your payments strategy to ensure you’re set up for success. Due to our revenue share model, we only win when you do: so we’re financially incentivized to help you succeed.

If you ever need help, you can reach us via phone, email, or Slack. We also offer level 2 merchant support: this means if your merchants have an urgent payment issue you can’t fix, we can talk you through how to resolve the issue or speak directly to the merchant.

Book a call to learn more about how we can support your payments strategy.

 Stripe Connect¹

Stripe Connect is an embedded payments solution designed for marketplaces and SaaS platforms. They charge a flat fee of 2.9% + $0.30 USD per online transaction, with no fixed monthly fee.

Stripe Connect doesn’t offer native omnichannel payments out of the box. To support a true omnichannel experience, you typically need to combine Connect with Stripe Terminal for in-person payments and build shared tokenization so payment details can be securely reused across online, in-store, and phone channels. In practice, that means more implementation work if you want a single, unified customer and payment flow across touchpoints.

On the user experience side, Stripe Connect is not fully white-label by default. You can customize parts of the onboarding and dashboard experience, but a fully white-labeled flow typically requires additional build work and, in some cases, creating your own onboarding UI.

Stripe Connect uses the same ticket-based infrastructure as Stripe’s main platform.

Worldpay for Platforms²

Worldpay for Platforms is an embedded payments solution built for software companies and platforms. It supports configurable fee models, so you can set your own merchant pricing using fixed or percentage-based fees, rather than being locked into a provider’s standard rate.

Their API is best described as multi-channel with optional omnichannel capabilities. It can support cross-channel tokenization and in-person payments, but a truly unified omnichannel flow depends on how you implement it and which products you use across online, in-store, and phone.

White labeling is also not offered by default. You can typically brand parts of the merchant experience, but a fully white-labeled onboarding and portal experience usually requires additional setup and, in some cases, building your own UI.

Worldpay for Platforms offers three models: integrated payments (referral), PayFac as a Service, and PayFac developer options. Support is provided via email through a ticket-based system.

Finix³

Finix is a PayFac-as-a-Service provider used by software platforms, marketplaces, and businesses that want more control over payments without building a full PayFac stack from scratch.

Pricing is usually offered on a flat-rate or interchange-plus basis, and rates can vary by region, like the US versus Canada. You can also tune your fee setup to better match your model, like offering volume-based discounts or using different pricing for specific transaction types.

On channels, Finix supports multi-channel acceptance, and you can get to a true omnichannel experience if you implement shared tokenization across touchpoints. It also offers white-label capabilities across key parts of the merchant journey, including embedded onboarding, branded emails, reporting, and chargeback workflows.

Support includes 24/7 coverage for urgent issues, plus email and ticket-based support for everything else.

Read more about Finix:

• Finix pricing review: Pricing model, extra fees, and alternatives for SaaS
• Finix vs Stripe: Comparing leading SaaS payment solutions

Monetize white-label, omnichannel payments with a single API integration and true revenue share model

Choosing the right payment API can feel overwhelming given all the available options. While most major APIs are solid, they vary in omnichannel capabilities, white-label options, and merchant support.

Fiska provides a uniquely tailored solution that balances control, flexibility, and operational simplicity and enables you to offer a seamless, branded payment experience.

Ready to get set up with embedded payments? Book a call with our team to learn more about how we can help.

FAQ: Top payment APIs for SaaS platforms

How is a payment API different from a payment gateway?

A payment API is the developer-friendly layer that lets your SaaS platform securely capture and send payment data (for example, card details or ACH information) from your product to the rest of your payment infrastructure. Most payment APIs also support common building blocks like authentication, webhooks, SDKs, and a sandbox environment so your team can test payment flows safely.

A payment gateway receives that data and performs critical checks like card verification, fraud prevention/fraud protection, and PCI controls aligned with PCI DSS requirements. It then routes the transaction through the relevant card networks and banks for authorisation and settlement as part of the broader payment processing flow.

What’s the difference between omnichannel and multi-channel payments?

Multi-channel means you accept online payments in multiple separate channels, like your website, mobile app, or in-person, but the systems don’t automatically share customer identity, reporting, or reconciliation. That can create fragmented payment flows and make it harder for SaaS companies to streamline operations across their ecosystem.

Omnichannel payments unify those channels into one payment platform, so customer profiles, transactions, reporting, and payment methods connect across touchpoints. For growing SaaS businesses, that makes it easier to scale, improve customer experience, and support use cases like unified refunds, cross-channel subscriptions, and consolidated analytics.

Sources:

¹ https://stripe.com/connect

² https://platforms.worldpay.com/en/embedded-payments

³ https://finix.com/pricing/platforms

*Disclaimer: Competitor features, capabilities, and pricing are summarized from publicly available product pages and documentation at the time of writing. Details may vary by region, use case, integration approach, and commercial agreement, and providers may change their offerings at any time. This content shouldn’t be relied on as a definitive statement of any provider’s functionality. For the most up-to-date information, confirm directly with each provider.