Adding a second payment gateway doubles your integration code. Adding a third triples it. Each provider has its own API structure, error formats, webhook signatures, and breaking changes. Over 70% of large enterprises now use multi-provider payment systems (Grand View Research), but the question is whether they’re maintaining separate integrations or routing through an abstraction layer.
Key numbers:
- 300-800 developer hours for multi-gateway direct implementation
- 50-70% of TCO is ongoing maintenance (Gartner)
- 70%+ of large enterprises use multi-provider payment systems
- 53% of merchants use orchestration platforms, improving success rates by 26%
- 20-50ms latency overhead for abstraction layer (worth the trade-off)
This guide covers the architecture patterns for multi-gateway payment integration: when direct integrations make sense, when abstraction pays off, and how to adopt an orchestration layer without ripping out working code.
Why multiple gateways require a different architecture
Direct integration to a single PSP is straightforward. The SDK handles authentication, the API accepts charges, webhooks confirm outcomes. The code is tightly coupled to that provider’s API surface, but tight coupling to one provider is manageable.
The problems start with provider two.
Each PSP has its own API quirks: different authentication patterns, different idempotency key handling, different webhook payload structures. Payments Dive reports that integrating and maintaining multiple PSP connections requires significant IT resources, with each additional provider extending project timelines and increasing maintenance costs.
The naive approach duplicates code for each provider:
// Provider-specific implementations scattered across codebase
async function chargeWithStripe(amount, currency, token) {
return stripe.charges.create({ amount, currency, source: token });
}
async function chargeWithAdyen(amount, currency, token) {
return adyen.payments({ amount: { value: amount, currency }, paymentMethod: { token } });
}
async function chargeWithBraintree(amount, currency, token) {
return gateway.transaction.sale({ amount, paymentMethodToken: token });
}This works until you need to add retry logic, failover, or a fourth provider. Then you’re maintaining parallel implementations of the same business logic across different API surfaces.
The integration maintenance problem at scale
Multi-gateway implementation takes 300-800 developer hours for direct API integration with routing logic (Neontri). At $100-200 per hour, that’s $30,000-$120,000 before accounting for ongoing maintenance.
The ongoing cost is worse. According to Gartner, maintenance and support account for 50-70% of total cost of ownership for software systems. Payment infrastructure is not a build-once project. It requires continuous updates for:
- Provider API version changes and deprecations
- New authentication requirements (3DS2 updates, SCA changes)
- Webhook format changes
- New error codes and decline reasons
- Security patches and compliance updates
Building payments infrastructure typically requires at least six engineers plus a product manager (Paddle). Those are engineers not building the features your users actually pay for.
The maintenance burden compounds when you need to keep multiple providers in sync. A change to your checkout flow requires updating the implementation for every connected gateway.
Architecture patterns for multi-gateway systems
The solution is an abstraction layer between your application code and the payment providers. This pattern has several names: payment orchestration layer, payment abstraction, anti-corruption layer.
The core principle: your application code calls one interface. The abstraction layer handles provider-specific translation.
┌─────────────────────────────────────────┐
│ Application Code │
│ (checkout, subscriptions, refunds) │
└─────────────────┬───────────────────────┘
│
▼
┌─────────────────────────────────────────┐
│ Payment Abstraction Layer │
│ - Unified API │
│ - Routing rules │
│ - Error normalization │
│ - Failover logic │
└───────┬─────────┬─────────┬─────────────┘
│ │ │
▼ ▼ ▼
┌───────┐ ┌───────┐ ┌───────┐
│Stripe │ │ Adyen │ │Braint.│
└───────┘ └───────┘ └───────┘With this architecture, adding a new provider means configuring the abstraction layer, not changing application code. Failover between providers happens at the abstraction layer. Error formats normalize before reaching your business logic.
This is what 53% of merchants have implemented through orchestration platforms, improving success rates by over 26% (Grand View Research).
What a payment abstraction layer looks like in code
The abstraction layer exposes a single interface regardless of which provider handles the transaction:
// Application code calls unified interface
const result = await paymentOrchestrator.charge({
amount: 5000,
currency: 'USD',
paymentMethod: tokenizedCard,
metadata: { orderId: '12345' }
});
// Result is normalized regardless of provider
if (result.status === 'succeeded') {
// Handle success
} else if (result.status === 'requires_action') {
// Handle 3DS challenge
} else {
// Handle failure with normalized error
console.log(result.error.code); // e.g., 'card_declined'
console.log(result.error.message); // Human-readable message
}The routing decision happens inside the orchestrator based on configured rules:
// Routing configuration (not application code)
const routingRules = {
default: 'stripe',
rules: [
{ condition: 'currency === EUR', provider: 'adyen' },
{ condition: 'amount > 10000', provider: 'braintree' },
{ condition: 'card.country === DE', provider: 'adyen' }
],
fallback: ['adyen', 'braintree'] // Failover order
};Your application code doesn’t know or care which provider processed the transaction. It receives a normalized response and handles business logic accordingly.
A payment orchestration platform implements this pattern as a managed service. You integrate once; the platform handles provider connections, routing, failover, and normalization.
Incremental adoption without replacing existing integrations
The common objection: “We already have Stripe in production. We’re not rewriting our payment code.”
You don’t have to. Orchestration layers sit alongside existing integrations, not in place of them.
The incremental path:
- Keep existing integration running. Your current Stripe code continues processing transactions exactly as before.
- Route new providers through the abstraction layer. When you need to add Adyen for European transactions, integrate via the orchestration layer instead of direct integration.
- Migrate existing providers gradually. As you build confidence, move Stripe traffic through the orchestration layer. Your application code changes from calling Stripe directly to calling the unified interface.
// Phase 1: Direct Stripe + orchestrated Adyen
if (shouldUseAdyen(transaction)) {
return orchestrator.charge(transaction);
} else {
return stripe.charges.create(transaction);
}
// Phase 2: Everything through orchestrator
return orchestrator.charge(transaction);This approach de-risks adoption. You can test the orchestration layer with lower-volume traffic before migrating your primary provider. If something goes wrong, you can fall back to direct integration without a full rewrite.
62% of businesses globally have adopted multi-provider payment gateways (Grand View Research). The question is whether to build the abstraction layer yourself or use a platform that provides it.
Error handling and failover across providers
Each payment provider returns errors differently. Stripe uses specific error codes. Adyen returns refusal reason codes. Braintree has its own decline categories. Without normalization, your error handling code branches for every provider:
// Without abstraction: provider-specific error handling
if (provider === 'stripe') {
if (error.code === 'card_declined') { /* ... */ }
} else if (provider === 'adyen') {
if (error.refusalReasonCode === '05') { /* ... */ }
} else if (provider === 'braintree') {
if (error.status === 'processor_declined') { /* ... */ }
}An abstraction layer normalizes errors into a consistent format:
// With abstraction: unified error handling
if (error.category === 'card_declined') {
// Handle decline regardless of provider
if (error.retryable) {
return orchestrator.retry(transaction, { excludeProvider: error.provider });
}
}The orchestration layer also handles automatic failover. When a provider returns a soft decline or times out, the layer can retry through an alternate provider before returning a failure to your application.
Intelligent routing engines reduce transaction failures by nearly 20%. AI-based routing modules cut authorization declines by up to 12% in high-volume markets. These optimizations happen at the abstraction layer without changes to application code.
The trade-off is latency. An orchestration layer adds a network hop, typically 20-50ms per request. For most applications, this trade-off is worth the reduction in integration maintenance and improved success rates.
Making the build vs. buy decision
You can build a payment abstraction layer internally. The architecture patterns are well-documented. The question is whether building payments infrastructure is the best use of your engineering team’s time.
| Factor | Build internally | Use orchestration platform |
|---|---|---|
| Upfront effort | 300-800 developer hours | Days to weeks |
| Team required | 6+ engineers + PM | Existing team |
| Ongoing maintenance | 50-70% of TCO | Handled by platform |
| New providers | Months per integration | Configuration |
| Best for | Payments-as-core-product companies | Most engineering teams |
The build approach makes sense when payments are your core product. If you’re building a payments company, owning the infrastructure is strategic.
For most teams, the math favors buying. The intelligent routing and optimization capabilities of a dedicated platform typically exceed what an internal team can build and maintain alongside other priorities.
Frequently asked questions
Can I add an orchestration layer without replacing my existing Stripe integration?
Yes. Orchestration layers sit alongside existing integrations. Keep your current Stripe code running, route new providers through the abstraction layer, and migrate existing traffic gradually as you build confidence.
How does multi-gateway routing affect PCI scope?
An orchestration platform handles card data on your behalf, reducing your PCI scope. Your integration touches tokens, not raw card numbers. The platform maintains PCI compliance for the card handling.
What happens when one payment gateway goes down?
With multi-gateway architecture, transactions automatically route to backup providers. The failover happens at the orchestration layer, not in your application code. Your application receives a normalized success or failure regardless of which provider processed the transaction.
How do I handle different error formats from different gateways?
Orchestration layers normalize error responses into a consistent format. You handle one error structure regardless of which underlying provider failed. The layer translates provider-specific error codes into standard categories your application can handle uniformly.
What’s the latency overhead of an orchestration layer?
Typically 20-50ms per request. The trade-off is worth it when you factor in the engineering time saved on maintaining multiple direct integrations and the improved success rates from intelligent routing and failover.
