FinFusion

Integration Best Practices

Following these best practices will help ensure a robust and efficient integration with FinFusion.

Security Best Practices

API Authentication

API Key Management

Secure handling of API keys

Recommendations:
  • Store keys in environment variables
  • Rotate keys every 90 days
  • Use different keys for different environments
  • Implement key access logging 
// Bad - hardcoded keys
const client = new FinFusion({ apiKey: 'sk_123456' });

// Good - environment variables
const client = new FinFusion({
  apiKey: process.env.FINFUSION_API_KEY,
  environment: process.env.FINFUSION_ENV
});

Request Signing

Verify request authenticity

Recommendations:
  • Implement webhook signatures
  • Validate all incoming requests
  • Use constant-time comparison
  • Handle signature expiration 
// Verify webhook signature
const isValid = await finfusion.webhooks.verifySignature({
  payload: requestBody,
  signature: headers['x-finfusion-signature'],
  timestamp: headers['x-finfusion-timestamp']
});

Error Handling

Retry Logic

Handle transient failures gracefully

// Configure retry options
const client = new FinFusion({
  apiKey: process.env.FINFUSION_API_KEY,
  retryConfig: {
    maxRetries: 3,
    initialDelay: 1000,
    maxDelay: 5000,
    backoffFactor: 2,
    retryableStatuses: [408, 429, 500, 502, 503, 504]
  }
});

Best Practices:

  • Implement exponential backoff
  • Set maximum retry attempts
  • Handle rate limits appropriately
  • Log retry attempts

Error Classification

Properly categorize and handle errors

try {
  await finfusion.payments.create(paymentData);
} catch (error) {
  if (error instanceof FinFusion.errors.ValidationError) {
    // Handle validation errors
    logger.warn('Validation error:', error.details);
    return handleValidationError(error);
  } else if (error instanceof FinFusion.errors.RateLimitError) {
    // Handle rate limiting
    logger.warn('Rate limit exceeded:', error.retryAfter);
    return handleRateLimit(error);
  } else if (error instanceof FinFusion.errors.AuthenticationError) {
    // Handle authentication issues
    logger.error('Authentication failed:', error.message);
    return handleAuthError(error);
  } else {
    // Handle unexpected errors
    logger.error('Unexpected error:', error);
    return handleUnexpectedError(error);
  }
}

Rate Limiting

Rate Limits

Type Rate Burst Scope
Standard 100 requests per minute 150 requests Per API key
High Volume 1000 requests per minute 1500 requests Enterprise accounts 
// Implement rate limiting handler
const rateLimiter = new FinFusion.RateLimiter({
  maxRequests: 100,
  perMinute: 1,
  burst: 150,
  onLimitReached: async (error) => {
    logger.warn('Rate limit reached:', error);
    await notifyTeam(error);
  }
});

// Use rate limiter
const client = new FinFusion({
  apiKey: process.env.FINFUSION_API_KEY,
  rateLimiter: rateLimiter
});

Performance Optimization

Batch Processing

Optimize multiple operations

// Instead of multiple single requests
const results = await Promise.all([
  finfusion.customers.create(customer1),
  finfusion.customers.create(customer2),
  finfusion.customers.create(customer3)
]);

// Use batch API
const results = await finfusion.customers.createBatch([
  customer1,
  customer2,
  customer3
], {
  batchSize: 100,
  continueOnError: true
});

Caching

Implement efficient caching

// Configure caching
const cache = new FinFusion.Cache({
  ttl: 3600, // 1 hour
  maxSize: 1000,
  invalidation: {
    patterns: ['customer.*', 'payment.*'],
    onInvalidate: async (key) => {
      logger.info('Cache invalidated:', key);
    }
  }
});

const client = new FinFusion({
  apiKey: process.env.FINFUSION_API_KEY,
  cache: cache
});

Monitoring

  • Request latency
  • Error rates
  • Cache hit ratio
  • Rate limit usage
  • Batch efficiency 
// Configure monitoring
const metrics = new FinFusion.Metrics({
  enabled: true,
  detailed: true,
  reporter: {
    type: 'prometheus',
    endpoint: '/metrics'
  },
  alerts: {
    errorRate: {
      threshold: 0.05,
      window: '5m'
    },
    latency: {
      p95: 1000,
      p99: 2000
    }
  }
});
Always test your integration thoroughly in the sandbox environment before deploying to production.