Building integrations feels like walking a tightrope. One side is the promise of seamless automation: Stripe payments flowing into your CRM, Slack notifications triggered by user actions, data syncing effortlessly between systems. The other side is the reality: broken webhooks, failed API calls, and cascading failures that take down your entire app.
After years of watching teams struggle with integrations, I've learned this: the difference between integrations that work and integrations that break isn't the tools you choose. It's the architecture you build them on.
This guide covers some key questions about building backend integrations that scale, recover gracefully, and don't become your team's biggest source of production incidents.
How do I receive and process webhooks reliably?
Webhooks are promises made by external systems, and like all promises, they sometimes get broken. Your webhook handler needs to be more resilient than the systems sending to it.
The golden rule: Acknowledge first, process later.
Here’s actual production code that illustrates how to handle a webhook:
// Webhook endpoint structure
app.post('/webhooks/stripe', async (req, res) => {
// 1. Verify the signature FIRST
const signature = req.headers['stripe-signature'];
let event;
try {
event = stripe.webhooks.constructEvent(req.body, signature, process.env.STRIPE_WEBHOOK_SECRET);
} catch (err) {
return res.status(400).send('Invalid signature');
}
// 2. Check for duplicates using idempotency
const existingEvent = await db.webhookEvents.findUnique({
where: { externalId: event.id }
});
if (existingEvent) {
return res.status(200).send('Already processed');
}
// 3. Store the raw event BEFORE processing
await db.webhookEvents.create({
data: {
externalId: event.id,
type: event.type,
payload: event.data,
status: 'pending'
}
});
// 4. Acknowledge receipt immediately
res.status(200).send('Received');
// 5. Process asynchronously
await processWebhookAsync(event);
});
When a webhook hits your endpoint, immediately return a 200 status and queue the actual processing work. This prevents the sending system from timing out and retrying while you're still processing the first request.
Your webhook handler should validate the payload signature, extract the essential data, and pass it to a background job system. The webhook endpoint itself should be as thin as possible. It needs just enough logic to say "I got this" and hand it off.
Why this matters: Ideally, we want to strive for data idempotence so the system can operate deterministically. If a service sends multiple requests and errors due to timeouts from a pipeline that not only receives but also does the heavy processing, we’re introducing a bottleneck that can prevent downstream operations from completing.
As an example, Stripe will retry failed webhooks for up to three days. If your handler times out because you're doing heavy processing inline, you'll get duplicate events, missed events, and angry customers wondering why their payments aren't reflected in your app.
Always return a 200, then process.
How do I call third-party APIs reliably?
Third-party APIs fail. This is something that will happen. Your integration architecture needs to assume failure and design around it.
The three pillars of reliable API calls:
- Exponential backoff with jitter: When an API call fails, wait before retrying. Start with a short delay, then double it each time. Add randomness (jitter) so all your retries don't happen at exactly the same time.
- Circuit breakers: If an API is consistently failing, stop calling it temporarily. This prevents your app from wasting resources on calls that will fail and gives the external service time to recover.
- Graceful degradation: Design your app so it can function (albeit with reduced features) when external APIs are down. Cache critical data locally so you're not completely dependent on external services.
The key insight is treating external API calls as inherently unreliable operations that require their own error handling strategy, separate from your core application logic.
How do I sync data between systems without losing my mind?
Data synchronization is where most integration projects go to die. The temptation is to build real-time, bidirectional sync that keeps everything perfectly in sync all the time.
Don't.
Start with unidirectional sync with a clear "source of truth" for each piece of data. Your CRM owns customer data. Your billing system owns subscription data. Your product owns usage data. When you need data to flow between systems, pick one direction and stick with it. This is how I leverage Xano as the main database and orchestration hub. Data flows directionally INTO Xano.
Use event-driven patterns: Instead of polling for changes, emit events when data changes in your system and let other systems subscribe to those events. This reduces API calls, improves performance, and makes your data flow more predictable. This looks like webhooks ready to receive events from the external services.
Build for eventual consistency: Accept that different systems will be slightly out of sync, and design your application logic to handle that gracefully. Perfect real-time sync is expensive and fragile. Eventual consistency is cheap and resilient. This could look like a CRON job that runs every 6 hours and reconciles data between services.
How do I integrate with Stripe, Slack, HubSpot, and other popular services?
Each major SaaS platform has its own quirks, but the patterns are surprisingly consistent once you know what to look for.
For Stripe: Focus on webhook events, not API polling. Stripe's webhook system is robust, but you need to handle duplicate events and implement proper idempotency. Always verify webhook signatures and process events asynchronously.
For Slack: Use the Events API for receiving messages and actions, not the older Real-Time Messaging API. Rate limiting is aggressive (1 request per second for most endpoints), so implement proper queuing and respect the rate limits.
For HubSpot: Their API is powerful but complex. Start with the simpler endpoints (contacts, companies) before diving into custom objects and workflows. Their webhook system is reliable but requires proper subscription management.
The universal pattern: Every major SaaS integration follows the same flow: authenticate with OAuth, subscribe to webhooks for real-time events, use their REST API for actions, and implement proper error handling and rate limiting throughout.
When should I use Zapier (or similar tools) vs. building my own backend integration?
This is the million-dollar question, and the answer depends more on control and complexity than on technical capability.
Use Zapier (or similar tools like n8n) when:
- You need quick, simple automations between well-supported services
- Non-technical team members need to create or modify integrations
- The integration logic is straightforward (if this, then that)
- You're comfortable with the limitations of pre-built connectors
Build your own when:
- You need complex business logic that doesn't fit into simple trigger-action patterns
- You need to transform data in ways that aren't supported by no-code tools
- You need fine-grained error handling and retry logic
- You need to integrate with internal systems or custom APIs
- You want to save money
The key insight is that Zapier and other tools excel at simple, reliable connections between popular services, but it struggles with complex logic, custom error handling, and unique business requirements. Once you start scaling, the cost can get heavy, fast.
How do I build event-driven integrations that don't break?
Event-driven architecture sounds complex, but it's really about two simple principles: events are facts, and facts don't change.
Design events as immutable records of what happened, not commands for what should happen. "User signed up" is better than "Send welcome email" because it lets multiple systems react to the same event in different ways.
Make events self-contained. Include all the data needed to process the event in the event payload itself. This prevents race conditions where the event processor tries to fetch related data that's changed since the event was emitted.
Implement proper event versioning from day one. Your event schema will evolve, and you need a way to handle both old and new event formats gracefully.
The magic of event-driven integrations is that they decouple systems naturally. Your user service doesn't need to know about email systems, analytics systems, or billing systems. It just emits "user signed up" events, and other systems can subscribe to those events independently.
How do I prevent integrations from breaking my core application?
Integration failures should never cascade into your core application.
Implement proper timeouts and resource limits. Set timeouts on external API calls and limit the resources (CPU, memory) that integration processing can consume. Ideally, close the connection after 30 seconds of waiting.
Build comprehensive monitoring and alerting. You need to know immediately when integrations start failing so you can take action before users are affected. This looks like setting up triggers within business logic or within try/catch blocks that send to external systems (Slack, Discord) to notify you of issues.
Used cached data: Only implement a system that caches data if you can verify the data does stay the same. If data is dynamic, caching won’t help. If the data is static and remains the same, cache these values so you don’t have to requery the 3rd party integration.
The goal is to treat integrations as a separate concern from your core application, with their own infrastructure, monitoring, and failure modes.
How do I build API-first products that partners actually want to use?
Building APIs for external partners is different from building APIs for your own frontend. Partners have different needs, constraints, and expectations.
Start with clear, comprehensive documentation. Your API documentation is often the first impression partners have of your product. Make it interactive, include realistic examples, and keep it updated.
Design for developer experience, not just functionality. Consistent naming conventions, predictable response formats, and helpful error messages make the difference between an API that partners love and one they tolerate.
Implement proper versioning and deprecation policies. Partners build their businesses on your API. Breaking changes without proper notice and migration paths will damage those relationships.
Provide webhooks, not just REST endpoints. Partners don't want to poll your API constantly. Give them webhooks so they can react to events in real-time.
The key insight is that external APIs are products in their own right, with their own users (developers) who have their own needs and expectations.
What does production-ready integration architecture actually look like?
Production-ready integration architecture is boring, and that's the point. It's built around proven patterns, comprehensive error handling, and operational visibility.
Centralized integration layer: All external API calls and webhook processing go through a dedicated service or set of services. This makes it easier to implement consistent error handling, monitoring, and rate limiting.
Comprehensive logging and tracing: Every integration event should be logged with enough detail to debug failures. Distributed tracing helps you follow requests across multiple services and external APIs.
Graceful degradation: Your core application should continue working even when integrations are down. This might mean showing cached data, disabling non-essential features, or queuing actions for later processing.
Regular integration health checks: Monitor the health of your integrations proactively. Don't wait for users to report problems—build monitoring that detects integration issues before they affect users.
The goal is to build integration architecture that's reliable enough that you rarely think about it, and observable enough that when problems do occur, you can diagnose and fix them quickly.
Ready to build bulletproof integrations?
The difference between toy integrations and production integrations is reliability. The patterns in this guide aren't theoretical. They're battle-tested solutions to real problems that every growing product eventually faces.
Whether you're building your first webhook handler or scaling to hundreds of integrations, the principles remain the same: isolate failures, make everything observable, and never let external dependencies break your core product.
Want to implement these patterns without building everything from scratch? Platforms like Xano provide the backend infrastructure to handle queues, logging, and API management so you can focus on your integration logic instead of the plumbing. But don’t take my word for it.
