API Integration Best Practices: Connecting Your Business Systems

Modern businesses run on integrations. Your CRM talks to your email platform, which talks to your analytics, which feeds your dashboard. When it works, it's magic. When it breaks, it's chaos.

The Integration Reality

We've built hundreds of integrations. Here's what we've learned: APIs change, services go down, data gets messy. Building integrations that survive real-world conditions requires deliberate practices.

Design for Failure

The API will fail. Plan for it:

• Retry logic: Automatic retries with exponential backoff
• Circuit breakers: Stop hammering a down service
• Fallbacks: What happens when the integration is unavailable?
• Queuing: Store requests and process when service recovers

// Exponential backoff example
async function callWithRetry(fn, maxRetries = 3) {
    for (let i = 0; i < maxRetries; i++) {
        try {
            return await fn();
        } catch (err) {
            if (i === maxRetries - 1) throw err;
            await sleep(Math.pow(2, i) * 1000); // 1s, 2s, 4s
        }
    }
}

Version Your Integrations

APIs change. Your integration code should be versioned separately from your main application:

• Use API version numbers in endpoints (v1, v2)
• Abstract API calls behind your own interface
• Test against multiple API versions during transitions

Handle Data Transformation Carefully

Data from external APIs rarely matches your internal format:

// Transform external data to internal format
function transformContact(externalContact) {
    return {
        id: externalContact.contactId || externalContact.id,
        name: formatName(externalContact),
        email: normalizeEmail(externalContact.email_address),
        phone: normalizePhone(externalContact.phone),
        source: 'salesforce',
        rawData: externalContact // Keep original for debugging
    };
}

Always keep the original data for debugging transformation issues.

Log Everything (But Carefully)

Good logging saves hours of debugging:

• Log request and response (redact sensitive data)
• Include correlation IDs to trace requests across systems
• Log timing information for performance monitoring
• Alert on error rate thresholds, not just individual errors

Use Webhooks When Available

Polling is expensive and slow. If the API offers webhooks, use them:

• Polling: Check every 5 minutes = up to 5 minute delay
• Webhooks: Instant notification when data changes

Webhooks require your system to receive HTTP calls, so ensure proper security (signature verification, HTTPS).

Rate Limiting

Most APIs have rate limits. Respect them:

• Track your usage against limits
• Implement throttling before hitting limits
• Queue non-urgent requests for batch processing
• Request higher limits if legitimately needed

Testing Integrations

Integration testing is hard but essential:

• Mock APIs: Test against recorded responses
• Sandbox environments: Use vendor sandboxes when available
• Contract testing: Verify API responses match expected schema
• Chaos testing: Simulate failures to verify resilience

Common Integration Patterns

Most integrations fall into these patterns:

• Sync: Keep two systems in sync (bidirectional or one-way)
• Event-driven: React to events in one system to update another
• Batch: Transfer data in scheduled batches
• Proxy: Your system as middleware between others

Choose the pattern that matches your data freshness requirements and system capabilities.

Building integrations that work reliably is challenging. If you're connecting critical business systems, let's talk about how we can help.