- A payment gateway is a necessity as it provides security, convenience, they are scalable and help you get paid quickly.
- In order to integrate the gateway, choose a provider such as Stripe or PayPal, set up the account, integrate the gateway, then test the checkout.
If you’re selling services online, then you need a way to accept payments from your customers. Period.
While there are a number of different payment processors out there, one option that you may want to consider is integrating a payment gateway into your website. At this point, you should already know what payment gateways are, but how do you go about integrating one into your site?
By the end of this article, you’ll know how to integrate a payment gateway into your agency website, and how it will help you keep track of invoices and payments.
Why do agencies need an integrated payment gateway?
Let’s cover a few of the reasons why you should think about integrating one into your website.
Here are five reasons why agencies should be taking advantage of payment gateways.
1) They’re secure
The role of a payment gateway is to process all data related to a payment by encrypting sensitive information, ensuring that everyone involved is protected. This is important not only for your customers’ safety, but also for your own peace of mind as a business owner.
2) They’re easy to use
Payment gateways are designed to be user-friendly, both for you as the merchant and for your customers. They should be easy to set up and integrate into your website, and they should offer a smooth and seamless checkout experience for your customers.
3) They’re convenient
A payment gateway allows you to accept payments 24/7, even when you’re not physically present to do so. This is especially convenient for businesses that sell services online or offer appointment-based bookings. Plus, thanks to the automated payments, you’re not required to chase clients for payments as you’d have to do when you manually invoice them.
4) They’re scalable
As your business grows, a payment gateway can grow with you. Most payment gateway providers offer various plans to accommodate businesses of different sizes, so you can always find one that fits your needs (and budget).
5) They help you get paid faster
A payment gateway can help you get paid faster by reducing the time it takes for payments to clear. With SPP, you can accept instant payments such as card payments that allow you to execute and deliver orders quickly.
Other payment methods such as SEPA or ACH need a few days’ time to clear. They are better suited for recurring subscriptions than one-time services.
Cost factors for payment gateway integrations
The cost of integrating a payment gateway can vary widely depending on several factors, such as the chosen provider, the complexity of the integration, and the specific business requirements. Let’s examine the typical costs involved.
Cost components
Integration costs: Integration costs vary widely depending on complexity. Basic integrations are typically free, with Stripe charging no setup fees and PayPal offering free account setup (Stripe.com, 2025). Custom development costs depend on project scope, developer rates, and integration complexity—businesses should obtain quotes from qualified developers or agencies for accurate estimates.
Monthly fees: Most basic payment gateway accounts don’t have any monthly fees—Stripe charges no monthly fees for standard accounts, and PayPal Business accounts have no base monthly fee. However, advanced services and enterprise features can incur monthly charges: Stripe Billing ranges from 0.5% to 0.8% of recurring revenue, while specialized gateway services like Authorize.Net charge $25-$30 monthly for advanced features.
Transaction fees: Current transaction fees as of 2025: Stripe charges 2.9% + $0.30 for online card payments, while PayPal charges 3.49% + $0.49 for PayPal Checkout transactions and 2.99% + $0.49 for standard merchant payments. Both providers offer custom pricing for high-volume businesses processing over $100,000 monthly.
Development and integration costs: If you need custom development or advanced integration features (like multi-currency support), these costs can range from $100 to $1,000 or more, depending on the developer's rates and project scope.
Additional costs: These may include fees for enhanced security features, PCI compliance, fraud prevention tools, and other premium services, potentially adding an extra 1% to 2% to your overall costs.
Sources:
Stripe Official Pricing: https://stripe.com/pricing
PayPal Merchant Fees: https://www.paypal.com/us/business/paypal-business-fees
According to Stripe's official pricing documentation, “custom pricing is available for businesses with large processing volumes,” with eligibility varying by market. Industry data from payment negotiation platform Vendr shows that Stripe typically revisits transaction rates for companies processing over $200,000 monthly, with businesses successfully negotiating reduced rates by demonstrating forecasted growth in transaction volume.
Cost factors
Business size and transaction volume: Larger businesses with higher transaction volumes often secure better rates, while smaller businesses might incur higher per-transaction fees due to lower volumes.
Type of payment gateway: Hosted gateways redirect customers away from your site, whereas integrated gateways keep them on-site. Although integrated gateways typically require more setup, they can offer lower transaction fees over time.
Geographic considerations: Costs can vary based on regional regulatory requirements and currency conversion needs, especially for international transactions.
Payment method compatibility: Different payment methods, such as credit cards and digital wallets, may have varying fee structures that impact overall costs.
Compliance factors
Importance of PCI DSS: Ensuring PCI DSS compliance is essential for businesses that integrate payment gateways. Failing to comply can lead to significant penalties, fines, and damage to reputation. A secure payment processing environment safeguards sensitive customer data, minimizing the risk of card skimming, identity theft, and other malicious activities.
When PCI DSS is required: Businesses handling sensitive payment data must comply with PCI DSS, including:
merchants with annual gross payments over $1 million
service providers processing 20,000 or more transactions monthly
companies storing or processing credit card information
third-party processors of sensitive payment data
Achieving PCI DSS compliance: To meet PCI DSS standards, set up a secure network, use strong access controls to protect important data, update software often, and have certified auditors check annually.
According to Stripe’s current (2025) developer documentation, all production integrations must implement webhook signature verification and Strong Customer Authentication (SCA) for European transactions. The Payment Card Industry Security Standards Council now requires tokenization for all stored payment data and mandates TLS 1.3 for payment processing communications.
How to integrate a payment gateway into a website
Now that we’ve gone over some of the reasons why agencies should use a payment gateway, let’s take a look at how to integrate one into your website.
Step one: choose a payment gateway provider
The first step is to choose a payment gateway provider. There are a number of different providers to choose from, so it’s important to do your research and select the one that’s right for your business.
When choosing a provider, there are a few things you’ll want to keep in mind:
Fees: Some providers charge monthly or annual fees, while others charge per-transaction fees. Make sure to compare the fees of each provider before making a decision.
Security: As we mentioned earlier, security is an important consideration when selecting a payment gateway. Be sure to check out each provider’s security features before making your final decision.
Integration: You’ll also want to make sure that the payment gateway you choose can be easily integrated into your website and other tools you use (e.g., SPP). Otherwise, you’ll likely run into some difficulties down the road.
While we can’t decide which provider is right for you, two of the most popular options on the market are PayPal and Stripe. Both are great places to start your search and can be integrated with SPP.
Step two: set up your account
Once you’ve chosen a provider, setting up your account is usually a pretty straightforward process. Most providers will require you to provide some basic information about your business, such as your business name and contact information.
You may also be asked to set up a payment method, such as a credit card or bank account. This is typically done so that the provider can verify your identity and ensure that you’re a legitimate business owner.
Step three: integrate payment gateway in website
The next step is to integrate the payment gateway into your website. This usually involves adding a few lines of code to your website’s checkout page, but working with a service like SPP can make the process even simpler.
How to integrate Stripe payment gateway in website
Navigate to Integrations → Stripe from your dashboard. Once you enter your Stripe login information, you’re ready to accept payments.
How to integrate PayPal payment gateway in website
Enable PayPal’s Instant Payment Notification (IPN) by navigating to PayPal’s Account Settings→ Notifications → Instant Payment Notification. Next, add https://clients.yoursite.com/paypal/ipn as the notification URL.
Once everything is connected, set up order forms and link their URLs to a button on your website. Most service providers have a pricing page with buy/subscribe buttons. Once clicked, the page redirects to the order form—and the payment gateway integration into your website is complete.
Step four: test your checkout process
Once you’ve integrated the payment gateway into your website, it’s important to test the checkout process to make sure everything is working properly. This usually involves making a test purchase using a dummy account.
SPP makes it easy to test your checkout process with a built-in sandbox mode. You can enable it by going to Settings → Payments and then clicking the “enable test mode” checkbox. Just make sure you remember to disable it before your clients start placing orders!
If everything goes smoothly, congratulations! You’re now ready to start accepting payments through your website.
Using professional services for integrations
If your team lacks a developer to integrate the payment gateway, consider hiring one or engaging agencies experienced with custom integration APIs. A benefit of dedicated agencies is the ease of vetting them through case studies and reviews, whereas a developer hired from platforms like UpWork may be more challenging to evaluate.
When seeking assistance with integration planning, ensure the presence of senior developers proficient in APIs and specializing in payment processing. While some developers may have general API knowledge, they might not understand payment processing intricacies.
Custom payment gateway development
Before considering custom development, evaluate the below factors.
When custom development makes sense:
Processing volume exceeds $10M annually
Unique business model requiring specialized flows
Integration with proprietary systems or legacy infrastructure
Specific regulatory requirements not met by standard providers
Hidden costs to consider:
PCI DSS compliance auditing: $5,000-$50,000 annually
Security monitoring and incident response
Regular penetration testing and vulnerability assessments
Ongoing maintenance and security updates
Staff training and certification requirements
Most agencies are better served by established providers like Stripe or PayPal, which offer enterprise-grade security and compliance at a fraction of custom development costs.
If you consider the custom development as a long-term investment, it does seem to make sense—but only for companies with large yearly revenues. Everyone else is better off with one of the popular payment gateways you can find in this list.
Payment gateway ROI calculator
Payment Gateway ROI Calculator
Calculate the financial impact of integrating automated payment processing into your agency
How This Calculator Works
📊 Calculation Methodology
This calculator uses industry-standard benchmarks and conservative estimates to project your payment gateway ROI:
💡 Key Assumptions
- • Time savings calculated at your specified hourly rate (capped at 15% of revenue)
- • Payment delays reduce from current timeline to 1-2 business days
- • Dispute resolution costs include staff time and administrative overhead
- • Client retention improvements scaled by agency size (3% for smaller, 5% for larger agencies)
- • Processing costs assume standard merchant account rates
- • All projections adjusted for realistic agency operations and scale
🎯 Next Steps
These projections are based on typical agency scenarios. Your actual results may vary depending on your specific client base, payment terms, and implementation approach. Consider starting with a pilot program to validate these assumptions.
Integrating payment gateway in website FAQ
How do I integrate payment gateway to my website?
Depending on the types of payment you want to accept, using tools such as Service Provider Pro allows you to easily add Stripe or PayPal, and accept payments within minutes. The alternative is using the options the payment gateway provider offers, for instance Stripe’s hosted pages.
How do I integrate PayPal gateway into my website?
In PayPal’s App Center, you can use the PayPal Checkout option and see multiple ways to integrate with your favorite tools. Software like SPP.co makes it especially easy to accept online payment by integrating directly with PayPal.
Is it hard to integrate a payment gateway?
Hosted payment gateways make it easy to implement their solutions even for those who are unfamiliar with programming. On top of that, you can use third party software that handle the gateway services by integrating with them directly.
What is the best payment method for a website?
Debit and credit cards are the most popular way to pay for services online. Depending where your customers are located, though, they might prefer other payment options, such as bank transfers or mobile payments.
How to accept payments on my website?
To accept payments on your website, integrate a payment gateway like Stripe or PayPal. This allows customers to securely enter their payment info and process transactions directly through your site.
How to integrate credit card payment on website?
To accept card payments on your website, choose a payment gateway (e.g., Stripe, PayPal) and sign up for an account. Use one of the available methods to connect the gateway to your website, either a ready-made checkout process, or a third-party tool like SPP.co.
Streamline payment processing with an integrated gateway
Payment gateways are a great way for agencies to take advantage of the convenience and security they offer. By following the steps to integrate payment a gateway in your website, you can start taking advantage of all they have to offer. Also read our post on how to add a payment gateway to your WordPress website if you’re running that CMS.
With SPP’s client portal, agencies can streamline the payment process even further with easy payment gateway integration options that give clients payment flexibility.
Real SPP customers have seen significant benefits from streamlined payment processing. Adam Steele from Loganix, a $3M/year SEO agency, reports: “Over its lifetime, we easily spent $60k building our old link building dashboard, and probably another 10-20k building the citation dashboard. We ended up folding both of these into SPP,” representing $70-80k in development cost savings.
This article provides general information about payment processing and should not be considered financial, legal, or business advice. Payment gateway fees, integration costs, and compliance requirements vary by provider and business circumstances. Consult with qualified financial and legal professionals before making payment processing decisions.
