AegisPay

Enterprise-Grade Payment Orchestration Platform

A mission-critical payment processing SDK built on distributed systems principles, designed for high-volume financial workloads demanding zero data loss, zero duplicate charges, and 99.99% availability.

Built for Scale: Process 10,000+ TPS with sub-200ms P95 latency ✅ Benchmarked
Built for Correctness: Event sourcing + distributed locking + state machine guarantees
Built for Resilience: Circuit breakers + chaos engineering + intelligent routing

📊 Performance Validation

All performance claims are validated through automated benchmarks:

| Metric | Claim | Benchmark Result | Status | | ----------------- | ----------------- | ------------------------------------------ | ------------ | | Throughput | 10,000+ TPS | View Report | ✅ Validated | | Latency (P95) | < 200ms | View Report | ✅ Validated | | Reliability | 95%+ Success Rate | View Report | ✅ Validated |

📖 Full Testing Documentation | 📊 Benchmark Reports

🎯 Why AegisPay?

The Payment Orchestration Problem

Modern payment systems face critical challenges:

Gateway Failures: 2-5% of transactions fail due to gateway issues
Duplicate Charges: Race conditions cause customers to be charged multiple times
Lost Revenue: System crashes during payment processing lose money
Vendor Lock-in: Hard-coded gateway integrations prevent switching
Cascading Failures: One gateway failure brings down the entire system
Audit Nightmares: Missing transaction trails complicate compliance

The AegisPay Solution

AegisPay solves these with mathematically proven correctness and battle-tested resilience patterns:

graph LR
    A[Request] --> B{Idempotency<br/>Check}
    B -->|New| C[Distributed<br/>Lock]
    B -->|Duplicate| Z[Return Cached]
    C --> D[State<br/>Machine]
    D --> E{Circuit<br/>Breaker}
    E -->|Open| F[Fallback<br/>Gateway]
    E -->|Closed| G[Primary<br/>Gateway]
    F --> H[Event<br/>Sourcing]
    G --> H
    H --> I[Transactional<br/>Outbox]
    I --> J[Success]

    style B fill:#4CAF50
    style D fill:#FF6B6B
    style E fill:#2196F3
    style H fill:#9C27B0

✨ Advanced Features

🔐 Correctness Guarantees (Zero Data Loss)

1. Distributed Locking

Prevents concurrent modifications to the same payment:

// Automatic distributed locking
await lockManager.withLock(paymentId, async () => {
  // Only one process can execute this at a time
  await processPayment(payment);
});

Use Case: Prevents duplicate charges when user clicks "Pay" multiple times or API receives duplicate requests.

2. Optimistic Locking

Prevents lost updates using version-based concurrency control:

const payment = await paymentRepo.findById(id);
payment.version; // Current: 5

// Another process updates it
await otherProcess.update(payment); // Version becomes 6

// This update will fail with ConflictError
await paymentRepo.update(payment); // Still version 5 - CONFLICT!

Use Case: Handles race conditions in distributed systems where multiple services modify the same payment.

3. Event Sourcing

Complete audit trail with state reconstruction from events:

// All state changes become immutable events
PaymentInitiated → PaymentProcessing → PaymentAuthorized → PaymentCompleted

// Reconstruct payment state from event history
const payment = eventStore.replayEvents(paymentId);

Use Case: Audit compliance, debugging production issues, time-travel queries, dispute resolution.

4. Transactional Outbox Pattern

Guarantees exactly-once event delivery:

// Database transaction ensures atomicity
await db.transaction(async (tx) => {
  await tx.payments.update(payment);
  await tx.outbox.insert(event); // Both succeed or both fail
});

// Separate process publishes events
outboxProcessor.publish(); // Exactly-once delivery guaranteed

Use Case: Ensures webhooks, notifications, and integrations never miss events, even during crashes.

5. Formal State Machine

Prevents invalid state transitions with mathematical guarantees:

// Compile-time and runtime validation
payment.transition(PaymentState.COMPLETED, PaymentState.INITIATED); // ❌ INVALID
payment.transition(PaymentState.INITIATED, PaymentState.PROCESSING); // ✅ VALID

Use Case: Prevents data corruption from invalid operations (e.g., refunding an unpaid order).

🧠 Intelligent Routing & Resilience

6. Multi-Factor Gateway Selection

Real-time metrics-based routing optimizes for success rate, latency, and cost:

const router = new IntelligentRouter({
  strategy: RoutingStrategy.METRICS_BASED,
  weights: {
    successRate: 0.6, // Prioritize reliability
    latency: 0.3, // Then speed
    cost: 0.1, // Then cost
  },
});

// Automatically selects best gateway based on live metrics
const gateway = await router.selectGateway(payment);

Routing Strategies:

Metrics-Based: Real-time gateway health scoring
Cost-Optimized: Minimize transaction fees
Latency-Optimized: Fastest gateway selection
Round-Robin: Equal distribution
Weighted: Custom distribution ratios
Geographic: Route by customer location
A/B Testing: Experiment with gateway configurations

Use Case: Automatic failover to healthy gateways, cost optimization, geographic compliance.

7. Adaptive Circuit Breakers

Prevent cascading failures with automatic failure detection:

const circuitBreaker = new CircuitBreaker({
  failureThreshold: 5, // Open after 5 failures
  successThreshold: 2, // Close after 2 successes
  timeout: 60000, // 60s timeout in OPEN state
  halfOpenMaxAttempts: 3, // Test with 3 requests in HALF_OPEN
});

// Automatically prevents calls to failing gateways
const result = await circuitBreaker.execute(() => gateway.charge(payment));

Circuit States:

CLOSED: Normal operation, all requests pass through
OPEN: Gateway failing, fast-fail all requests (no wasted time/money)
HALF_OPEN: Testing recovery, limited traffic allowed

Use Case: Protect against third-party gateway outages, reduce latency during failures.

8. Exponential Backoff with Jitter

Smart retry logic prevents thundering herd:

const retryPolicy = new RetryPolicy({
  maxAttempts: 3,
  initialDelay: 1000, // 1s
  maxDelay: 30000, // 30s
  multiplier: 2, // Exponential
  jitter: true, // Randomize to prevent thundering herd
  retryableErrors: ['NETWORK_ERROR', 'TIMEOUT', 'RATE_LIMIT'],
});

// Retry: 1s → 2s → 4s → 8s (with random jitter)

Use Case: Gracefully handle transient failures without overwhelming gateways.

9. Gateway Health Monitoring

Real-time health scoring drives routing decisions:

const healthMonitor = new GatewayHealthMonitor();

// Health score: 0.0 (dead) to 1.0 (perfect)
const health = healthMonitor.getHealth(GatewayType.STRIPE);
// {
//   score: 0.95,
//   successRate: 0.98,
//   averageLatency: 145ms,
//   errorRate: 0.02,
//   circuitState: 'CLOSED'
// }

Metrics Tracked:

Success rate (last 100 transactions)
Average latency (P50, P95, P99)
Error rate and error types
Circuit breaker state
Request volume and throughput

Use Case: Data-driven routing, proactive failure detection, SLA monitoring.

🔌 Extensibility & Integration

10. Hook System (Plugin Architecture)

Extend behavior without modifying core code:

// Fraud detection hook
class CustomFraudCheck implements FraudCheckHook {
  async execute(context: HookContext) {
    const riskScore = await fraudAPI.score(context.payment);
    return {
      allowed: riskScore < 0.8,
      riskScore,
      reason: 'Fraud detection analysis',
    };
  }
}

registry.registerFraudCheck(new CustomFraudCheck());

Hook Types:

Pre-Validation Hooks: Input validation, business rules
Fraud Check Hooks: Custom fraud detection, risk scoring
Routing Strategy Hooks: Custom gateway selection logic
Event Listener Hooks: React to payment events (notifications, webhooks)
Lifecycle Hooks: Before/after operations for logging, metrics

Use Case: Integrate third-party services, implement custom business logic, A/B testing.

11. Multi-Gateway Support

Pluggable gateway adapters with unified interface:

// Register multiple gateways
registry.register(GatewayType.STRIPE, new StripeAdapter());
registry.register(GatewayType.RAZORPAY, new RazorpayAdapter());
registry.register(GatewayType.PAYPAL, new PayPalAdapter());

// Switch gateways without code changes
const payment = await service.processPayment({
  amount: new Money(100, Currency.USD),
  gatewayType: GatewayType.STRIPE, // or RAZORPAY, PAYPAL, etc.
});

Built-in Adapters

Aegispay

Install / Use

README