Payment gateway integration for checkout that doesn't lose sales.
Hoop Interactive integrates Stripe, PayPal, Adyen, and other gateways into your website, app, or platform — with PCI-compliant handling, working webhooks, and a checkout that doesn't drop transactions.
What is payment gateway integration?
Payment gateway integration is the process of connecting your website, app, or platform to a third-party payment provider such as Stripe, PayPal, or Adyen, so customers can pay securely without your business handling raw card data directly. A developer implements the provider's API, sets up webhook handling for asynchronous events, and configures the checkout flow around your specific business logic.
Integration is a different project from building a payment gateway. A gateway is the underlying infrastructure that processes transactions — something companies such as Stripe and Adyen spend years and hundreds of millions of dollars building. Integration connects your product to that existing infrastructure through an API, which is faster, cheaper, and carries far less compliance burden than building processing infrastructure from scratch.
- Idempotent webhooks
- Duplicate events never double-charge or duplicate an order.
- Tokenized by default
- Raw card numbers stay off your servers, shrinking PCI scope.
- 3DS2 & SCA
- Strong authentication so EU and UK cards stop declining.
- Failover routing
- One processor outage does not stop all revenue.
Hosted, direct API, or orchestration?
Three integration models — and the trade-off each one makes between control and compliance scope.
| Integration model | What it is | Best fit |
|---|---|---|
| Hosted checkout | Customers are redirected to the provider's payment page to complete the transaction. | Businesses that want the smallest PCI compliance scope and fastest setup. |
| Direct API / non-hosted | Payment fields render on your own site, with data tokenized before it touches your servers. | Businesses that need full control over the checkout experience and branding. |
| Payment orchestration | A layer routing transactions across multiple gateways for redundancy and rate optimization. | High-volume businesses that need failover and processor flexibility. |
Where payment revenue actually leaks.
Why the build quality matters more than the provider you pick, and how to choose an integration model.
Why integration quality matters more than the gateway choice
Most major gateways process payments reliably; what actually causes lost revenue is a poorly built integration. Unhandled webhook failures leave orders stuck in limbo, missing 3D Secure support gets transactions declined in the EU, and a checkout with no retry logic loses customers the moment a card gets declined on the first attempt.
Hosted vs. direct integration: which do you need?
Use hosted checkout if you want to launch fast and keep PCI DSS compliance scope minimal. Use direct API integration if brand consistency in the checkout flow matters more than the fastest path to launch.
Why proper payment integration matters.
A checkout that fails silently, mishandles retries, or stores more card data than necessary costs you revenue and compliance risk you didn't need to take on.
Reduces cart abandonment
A checkout that handles declines and retries gracefully keeps the sale alive.
Keeps PCI scope minimal
Proper tokenization keeps most businesses in the lightest compliance tier.
Prevents lost orders
Idempotent handling means no unhandled or duplicate webhook events.
Supports digital wallets
Apple Pay, Google Pay, and others now drive a growing share of checkout volume.
Adds provider redundancy
One processor's outage doesn't stop revenue across the whole business.
Passes 3DS and SCA
Strong Customer Authentication requirements met in regulated markets.
Payment gateway services we offer.
We scope the engagement around your platform and payment volume, not a fixed provider.
New gateway integration
Stripe, PayPal, Adyen, Braintree, or Square integrated into your website, app, or platform from scratch.
Multi-gateway orchestration
A routing layer across multiple providers for redundancy, geographic coverage, or rate optimization.
Recurring billing & subscriptions
Subscription plans, prorated upgrades, failed-payment retries, and dunning management.
Mobile app payment SDKs
Native iOS and Android payment flows with Apple Pay and Google Pay support.
PCI DSS compliance setup
Tokenization and architecture decisions that keep your compliance scope as light as possible.
Gateway migration
Moving subscriptions, stored payment methods, and transaction history to a new provider without downtime.
Signs you need payment integration help.
Four situations send most product and finance leads to us for payment work.
- 01
Orders go missing after payment
Customers get charged, but the order never updates, because a webhook silently failed.
- 02
EU customers can't check out
Transactions decline because your integration doesn't handle 3D Secure and SCA correctly.
- 03
You're outgrowing a single provider
You need redundancy, better rates, or region-specific processors your current setup can't support.
- 04
You're launching subscriptions
Your product is moving to recurring billing and needs proper retry, proration, and dunning logic.
Common payment integration mistakes we help you avoid.
These five mistakes account for most of the lost-revenue payment bugs we get asked to fix.
No idempotency on webhook handling
CriticalDuplicate webhook events double-charge customers or create duplicate orders. We build idempotent handlers from day one.
Storing more card data than necessary
CriticalStoring raw card numbers expands your PCI DSS scope far beyond what most businesses need. We tokenize everything possible.
Skipping 3D Secure and SCA support
HighMissing strong authentication gets transactions declined in the EU and UK. We build 3DS2 support into every card integration.
One processor, no fallback
HighA single point of failure means one outage stops all revenue. We add failover routing for businesses at meaningful volume.
Poor decline and retry UX
MediumA checkout that just says "payment failed" loses the sale. We design clear, actionable retry flows for common decline reasons.
How we integrate your payment gateway.
Six stages, from first call to a live, tested checkout. We work in weekly sprints with a demo every Friday.
Discovery & compliance scoping
We review your payment volume, regions, and current setup, and define the PCI DSS scope the integration needs to stay inside.
1–2 weeks · DiscoveryIntegration architecture planning
We choose the integration model — hosted, direct API, or orchestration — and document the webhook and data flow.
3–5 days · PlanningDevelopment & webhook handling
We build the integration in weekly sprints, with idempotent webhook handlers and retry logic from the first commit.
2–16 weeks · DevelopmentSecurity & PCI testing
We test tokenization, 3DS flows, and data handling against PCI DSS requirements before any live testing.
1–2 weeks · Security QASandbox-to-live testing
We run test transactions across decline scenarios, refunds, and disputes before switching to live payment processing.
1–2 weeks · TestingLaunch & monitoring
We go live, set up transaction and webhook monitoring, and hand over a documented, commented codebase.
3–5 days · LaunchPayment integration cost and timeline.
Three factors drive the price: number of gateways, subscription billing complexity, and PCI compliance scope. Processing fees (typically 2–3% plus a flat fee) are billed separately by each gateway.
- Investment
- $5,000–$15,000
- Timeline
- 2–4 weeks
- Gateways
- 1 (Stripe, PayPal…)
- Checkout
- Hosted or standard API
- Webhooks
- Basic handling
- Investment
- $15,000–$50,000
- Timeline
- 4–10 weeks
- Gateways
- 2–3, multi-region
- Billing
- Subscriptions & dunning
- Mobile
- SDK integration
- Investment
- $50,000–$150,000+
- Timeline
- 10–20 weeks
- Routing
- Multi-gateway + failover
- Fraud
- Advanced detection
- Included
- Full reconciliation
The payment gateways we integrate.
Proven, well-documented providers, chosen for reliability and regional coverage.
Stripe
PayPal
Google Pay
Klarna (BNPL)
Node.js
PostgreSQL
AWSWays to work with us.
Pick the model that fits your project and team. All four include weekly demos and full code ownership.
Fixed-Scope Project
A defined gateway list, timeline, and price agreed before we start. You know the exact cost up front.
Best for fixed budgetsDedicated Team
Backend engineers working as an extension of your team through launch and beyond.
Best for larger buildsStaff Augmentation
A senior payments engineer added to your existing team to close a skills gap or add build capacity.
Best for existing teamsMaintenance Retainer
Ongoing webhook monitoring, gateway API updates, and troubleshooting for a system already live.
Best for live systemsEvery payment integration comes complete.
No hidden gaps. Each engagement includes everything you need to launch and maintain the integration.
- Compliance scoping
- A clear PCI DSS scope defined before any code gets written.
- Tokenized checkout
- Card data handled by the provider, not stored on your servers.
- Idempotent webhooks
- Event handling built to survive retries and duplicate deliveries.
- 3DS2 & SCA support
- Strong authentication built in for EU and UK card transactions.
- Decline & retry UX
- Clear, actionable checkout messaging when a payment fails.
- Sandbox testing
- Full test coverage across declines, refunds, and disputes.
- Transaction monitoring
- Alerts and dashboards wired in before launch, not after issues appear.
- Documented handover
- Clean, commented code and a repository you own outright.
Payment integrations we build across every sector.
The process stays the same. The compliance and volume needs change by industry.
Ecommerce & Retail
Checkout flows built for high-volume, multi-currency sales.
SaaS & Subscriptions
Recurring billing, proration, and dunning management.
Marketplaces
Split payments and payouts across multiple vendors.
Healthcare
Patient payment portals built for compliance requirements.
Real Estate
Rent, deposit, and application fee processing.
Education
Tuition and course payment processing with installment plans.
Nonprofits
Donation processing with recurring giving support.
Mobile Apps
In-app purchases and native payment SDK integration.
Explore more software services.
Payment gateway integration is one of twelve engineering areas we cover, under API & Integrations.
API Development
REST and GraphQL APIs built for your own product.
ExploreAPI Integrations
Connect to maps, messaging, AI, and identity providers.
ExploreEcommerce Development
Storefronts and order systems behind the checkout.
ExploreShopify Development
Hosted storefronts with Shopify Payments configured.
ExploreWooCommerce Development
Self-hosted stores with Stripe and PayPal wired in.
ExploreSaaS Platforms
Multi-tenant products with billing built in.
ExploreSecurity, QA & Maintenance
Security review and testing across the payment path.
ExploreNode.js Development
The backend layer handling webhooks and retries.
ExplorePayment gateway integration questions
The questions product and finance leads ask us most before starting a payment integration.
No. Payment gateway integration connects your website or app to an existing provider such as Stripe or PayPal through their API. Building a payment gateway means creating the processing infrastructure itself, which costs far more and carries a much larger compliance burden.
Payment gateway integration costs $5,000 to $150,000 or more, depending on scope. A single gateway integration costs $5,000 to $15,000, a multi-gateway or platform integration costs $15,000 to $50,000, and a payment orchestration layer costs $50,000 to $150,000 or more.
Payment gateway integration takes 2 to 20 weeks or more. A single gateway integration takes 2 to 4 weeks, a multi-gateway integration takes 4 to 10 weeks, and a payment orchestration layer takes 10 to 20 weeks or longer.
PCI DSS (Payment Card Industry Data Security Standard) is the security standard for any business that processes card payments. You need it at some level if you handle card data at all, but using tokenization and a hosted checkout keeps most businesses in the lightest compliance tier.
Yes. We build orchestration layers that route transactions across multiple gateways, so you get redundancy if one provider goes down and better rates by comparing processors per transaction type.
Yes. We build subscription billing, prorated upgrades, failed-payment retry logic, and dunning management on top of your chosen gateway's subscription API.
Tokenization replaces sensitive card data with a random token your systems can store and reuse safely. It matters because it keeps raw card numbers off your servers entirely, which sharply reduces your PCI DSS compliance scope.
Yes. We integrate Apple Pay, Google Pay, and other digital wallets alongside standard card payments, since wallets now account for a large and growing share of online checkout volume.
Yes. We migrate active subscriptions, stored payment methods, and transaction history to a new gateway in phases, so billing continues without interruption.
Yes. You own 100% of the integration code, delivered in a documented, ready-to-hand-over repository with no vendor lock-in beyond the payment provider itself.
Yes. We offer maintenance retainers covering webhook monitoring, gateway API updates, and troubleshooting for a payment system already live.
Yes. We sign an NDA before the discovery call, before you share any financial or business details with us.