What is API integration?
API integration is the engineering process of connecting two or more software systems through their Application Programming Interfaces so they exchange data and trigger actions in real time.
API integration is what makes modern software composable. CRMs talk to accounting platforms; analytics dashboards pull from operational systems; notifications fire across stacks. Done well, integrations turn point tools into a unified operational surface. Done badly, they create fragile chains where one outage cascades across the business. The discipline lives at the intersection of architecture, error handling, and observability — knowing when to use direct REST calls, when to introduce queues or event streams, when to use webhooks, and how to monitor for silent failures.
What it includes
- Authentication (OAuth, API keys, JWT, mTLS)
- Request and response handling with retries
- Rate limiting and backoff strategies
- Webhook endpoints and signature verification
- Event-driven architectures (queues, streams)
- Logging, observability, and error alerting
How it works
Map the integration
Document source, target, data flow, frequency, error handling expectations, and ownership. Architecture before code.
Choose the pattern
Sync REST for low-volume request-response. Webhooks for event-driven. Queues or streams for high-volume or fault-tolerance critical flows.
Implement with discipline
Retries, exponential backoff, idempotency keys, signature verification. Treat external APIs as unreliable.
Monitor in production
Alert on broken pipelines before users report them. Latency, error rates, queue depths — all observable.
Frequently asked
When should I use webhooks vs polling?
Webhooks when the source system supports them and event freshness matters. Polling when the source has no webhook support or when you control the cadence and want predictable cost.
What's the difference between REST and event-driven integration?
REST is request-response, synchronous, and simple. Event-driven (queues, streams) decouples producers from consumers, scales better, and survives transient failures. REST for simple CRUD; events for high-volume or fault-tolerance-critical flows.
How long does an integration build take?
A simple two-system integration ships in 2–4 weeks. Multi-system orchestrations with event-driven architecture run 6–12 weeks depending on scope and reliability requirements.