Payment Gateway Integration Services

A failed transaction can mean lost revenue.

A payment method your platform doesn't support or a subscription renewal that silently fails: the customer may retry, switch payment methods, and abandon the purchase entirely. Acropolium builds secure payment gateway integrations for web and mobile apps, CRMs, and ERPs. Our experienced team connects third-party payment gateway providers such as Stripe, PayPal, Authorize.Net, and custom payment APIs directly into your existing systems. That work draws on 23 years of building custom software for companies where a broken payment flow shows up on the P&L within days.

Signs Your Payment Infrastructure Needs an Upgrade

Payment infrastructure rarely fails all at once. It degrades gradually, until finance notices a pattern before engineering does. Chargebacks can climb quarter over quarter. Support tickets pile up with "my payment didn't go through" and nobody can say exactly why payments fail on a given attempt. It seems like there is no clear root cause behind any of them. Acropolium sees this pattern across clients who arrive suspecting something's wrong, and leave discovery with the actual number attached to it.

The signs compound as the business scales. A single gateway handling one currency works fine at low volume. Add international customers, a second product line, or subscriptions layered on top of one-time purchases, and that gateway starts forcing workarounds nobody budgeted for: limited payment methods supported, uncontrolled currency conversion fees, rising chargeback fees. Recurring billing scattered across manual processes and one-off workarounds. Acropolium's discovery phase maps this debt before recommending a single line of code.

Three signs point to a fixable problem rather than a full rebuild. A checkout that abandons customers because a payment method isn't supported. A CRM or ERP that never sees payment data without a manual export. Recurring billing running on workarounds, when a real integration would remove most of that manual work. Acropolium scopes each of these with solution architects and delivery leads in discovery, matching the fix to what the infrastructure actually needs.

Pavlo Zheldak

Chief Delivery Officer Acropolium

years of experience

455

delivered solutions

155

clients

Our Payment Gateway Integration Services

Acropolium covers the full payment gateway integration process, from a single checkout flow that lets you accept payments to a multi-gateway system spanning your entire product line. Each service below is scoped to close a specific revenue leak.

Online & eCommerce Payment Integration
A checkout that fails at the last step costs more than the transaction itself. It costs the customer who never comes back to try again. We integrate Stripe, PayPal, Authorize.Net, and other gateways directly into your checkout page, supporting various payments methods and flexible payment options for smooth online transitions. The result is a checkout flow built to convert, and never one that drops customers mid-transaction, drawing on our payment and billing systems expertise.
CRM & ERP Payment Integration
Payment data sitting outside your CRM or ERP means someone exports a CSV every time finance needs a real picture of revenue. Acropolium connects payment gateways directly into these systems the same way financial institutions already report them, using the same discipline behind our broader custom software development practice. Transaction data flows automatically into the tools your team already runs the business from, and finance gets accurate numbers without the manual chase.
Subscription & Recurring Billing
Recurring billing built on manual workarounds breaks the moment a card expires or a currency conversion goes wrong. Acropolium builds subscription billing systems that handle retries, dunning, and recurring payments automatically, so failed payment requests get resolved before revenue is lost. Automated retries and dunning reduce how often anyone has to chase down failed renewals by hand.
Mobile App Payment Integration
Mobile checkout carries its own constraints: smaller screens on mobile devices, in-app purchase rules, and users who abandon a flow the moment it feels slow. We build payment integrations specifically for mobile apps that prioritize secure transfer of data at every step, handling SDK-level implementation and platform-specific requirements. A well-built mobile checkout completes in a single tap, and never across three separate screens that give a customer time to reconsider.
Multi-Gateway & Multi-Currency Support
A single gateway handling one currency works until international customers show up and start forcing workarounds nobody planned for. Providing payment gateway API integration services, we build multi-gateway architectures that route international transactions by currency, region, or cost with transparent conversion rates. Your platform gains the flexibility to add a new market and skip rebuilding the payment layer from scratch every time.
Maintenance & Support
Payment gateways change their APIs and compliance requirements more often than anyone expects, introducing new security risks. Acropolium provides ongoing support with defined security measures after go-live. We monitor transaction health and patch integrations before a gateway change. Proactive transaction security monitoring means your team is less likely to find out about a problem from a dissatisfied customer first.

Payment Gateway Integration Methods Acropolium Uses

The right way to integrate a payment gateway depends on how much control your platform needs over the checkout experience, and how much PCI DSS compliance burden you're willing to take on. We pick the direct integration method that fits your specific risk tolerance and user experience goals.

Hosted Payment Gateway

The customer leaves your site, completes payment information on the provider's hosted page, and returns to your site for confirmation upon transaction completion. Behind the scenes, the transaction routes from the customer's bank through the acquiring bank to settle funds. This approach can reduce PCI DSS scope significantly, since payment-card data is handled by the provider though the merchant still retains applicable PCI DSS responsibilities (e.g., under SAQ A requirements). Acropolium implements hosted gateways for businesses that want to launch fast and avoid the compliance overhead of handling card data directly.

Self-Hosted Payment Gateway

Payment forms live directly on your site, giving you full control over the checkout page design and user experience. That control comes with more PCI DSS responsibility, since your systems can handle card data directly before sending it to the gateway, which can significantly increase compliance with the applicable PCI DSS requirements. We build self-hosted integrations for businesses where checkout conversion depends on a seamless, on-brand experience that a redirect would break.

Direct Post Integration

Payment data posts directly from the customer's browser to the gateway, bypassing your server entirely and keeping sensitive data out of your infrastructure. At the same time, the checkout still appears fully on your site. Direct Post can keep card data off your server, but it does not eliminate PCI DSS obligations. Eligible Direct Post implementations are generally assessed using SAQ A-EP, which has different requirements from qualifying redirect or iframe implementations. We use this integration method when conversion and compliance scope matter equally to the business.

Mobile Payment Gateway Integration

Mobile payment integrations may use provider SDKs, APIs, Apple Pay, Google Pay, or platform-specific billing systems, depending on the product and payment initiation method required. For digital goods and subscriptions, App Store and Google Play billing rules often apply and can determine which payment method is even permitted. Acropolium integrates these SDKs directly into your app, so mobile checkout completes in a tap instead of a multi-screen form built for desktop.

Payment Gateway API Integration

API integration can be architected to keep raw card data off your servers entirely, using tokenization or client-side collection, while keeping the checkout experience on your domain. The PCI DSS scope depends on how the integration is architected, not on the method itself. Acropolium builds these integration payment solutions using the same rigor within comprehensive custom API development services.

Payment Providers Acropoliums Integrates

Acropolium works with the major payment gateway providers businesses actually run on, plus custom APIs when a provider's standard offering doesn't cover what your business needs. The right provider for your needs depends on your transaction volume, geography, and business model.

Stripe

Stripe is a common choice for SaaS platforms, where billing complexity only grows as the product matures; revenue streams diversify across plans and usage tiers. Usage-based pricing, multi-party marketplaces, subscription tiers that shift mid-cycle: Stripe's API is handled by our team without forcing custom workarounds.

Square

Acropolium integrates Square for clients whose online and offline sales can't afford to live in separate systems. Retail and hospitality businesses running both a physical register and an online store need one platform that treats both channels the same way, and Square delivers that consistency.

Custom Payment APIs

Acropolium builds custom payment API connections from scratch when no off-the-shelf plugin exists for a regional processor or a bank's direct API. Drawing on the same discipline behind our broader custom API development services, your platform stops being limited to whichever providers happen to have pre-built connectors.

Authorize.Net

We integrate Authorize.Net when a client's priorities are fraud detection and predictable behavior over a broader feature set. Founded in 1996, it has one of the longest track records in e-commerce, with established recurring billing and fraud-control capabilities.

PayPal

For many consumer-facing businesses, offering PayPal alongside other payment methods can reduce cart abandonment. We integrate it as one option among several rather than a standalone gateway.

Braintree

Backed by PayPal but built with more flexibility, Braintree supports cards and digital wallets like Venmo and Apple Pay through one integration. Acropolium turns to it when a business wants PayPal's backing without PayPal's standalone checkout limitations.

Why Choose Acropolium For Payment Processing Integration?

A broken checkout doesn't cost you a transaction. It costs you, the customer. Acropolium builds payment integrations for companies that measure risk in real numbers.

Security and Compliance Built Into the Architecture

Card data handling, data encryption, and maintaining PCI DSS compliance get worked into the design from the first architecture conversation. We protect sensitive customer data, including credit card details, from the ground up. That matters most in payments, where a gap discovered after launch costs far more in fines and lost trust than one caught during design.

Enterprise & SaaS-Grade Payment Experience

Acropolium has built payment integrations for SaaS platforms handling real subscriber volume and enterprise systems processing secure transactions at scale. That track record spans 455+ delivered projects over 23 years, including businesses where a failed checkout shows up directly in revenue.

Ongoing Support After Go-Live

The team that built your integration stays on to monitor transaction processing health, patch issues when a gateway changes its API, and extend functionality as your business adds new markets or payment methods. Some of Acropolium's client relationships run 10+ years. Our clients stay with us because the experienced team remains accountable for how payments perform long after launch.

Senior-Level Involvement From Day One

Solution architects and delivery leads join discovery alongside sales before any contract gets signed. The scope, timeline, and cost you receive reflect what your payment infrastructure actually requires, cutting the risk of a mid-project surprise that blows the budget.

Direct Delivery

The engineers who scope your payment integration are the ones who build it. Acropolium never resells work to third-party contractors. One team stays accountable for the outcome, and there's no finger-pointing if a transaction starts failing six months after go-live.