API Integration

What is API integration?

An API (application programming interface) is a defined way for one piece of software to ask another for data or to perform an action. API integration uses those interfaces to connect systems. One system sends a request, for example "create this contact" or "give me all orders since yesterday", and the other responds with structured data, usually in JSON.

A common example: when a deal closes in the CRM, an integration calls the billing system's API to create the customer and the first invoice, then calls the project tool's API to open a delivery project. Data moves in seconds, in a consistent format, with no manual entry.

API integrations sit behind most modern business operations: syncing ecommerce orders to accounting, sending product usage data to a warehouse, pushing leads from forms into sales tools, or connecting support tickets to customer records. They can be built with custom code, through an iPaaS tool, or with connectors that the software vendors provide.

How do API integrations work?

Most business APIs follow a simple pattern. The calling system authenticates, usually with an API key or an OAuth token, sends a request to a specific endpoint, and receives a response with data or a status code.

Integrations run in one of two ways. With polling, a system checks another on a schedule, for example every few minutes, and asks what has changed. In event-driven integrations, the source system pushes a notification the moment something happens, often through a webhook. Many integrations use both: webhooks for speed and a scheduled check to catch anything missed.

A well-built integration also handles the less visible parts: mapping fields between systems with different structures, respecting rate limits, retrying failed calls, and logging every request so problems can be traced.

What should you check before building an API integration?

• API coverage: does the API expose the objects and actions you need, or only part of them?
• Limits and cost: are there rate limits, usage tiers or paid add-ons for API access?
• Data mapping: how do fields, IDs and statuses in one system correspond to the other?
• Direction and ownership: which system is the master for each field, and does data flow one way or both?
• Security: what access does the integration need, and how will credentials be stored?

The ownership question matters most. Two-way syncs without clear rules about which system wins create conflicts and duplicate records. Deciding upfront where each piece of data lives is the basis of a single source of truth.

What are the risks of API integrations?

Integrations fail quietly. A token expires, a vendor changes or retires an endpoint, a field is renamed, or a rate limit is hit during a busy period. If nobody is alerted, records drift out of sync and the problem surfaces weeks later as a wrong invoice or a missing lead.

Security is the other risk. Integrations often hold powerful credentials, so a leaked key can expose customer or financial data. Give each integration its own credentials with the narrowest permissions it needs, store them in a secrets manager rather than in code, and rotate them.

Treat integrations as production software: monitor them, log failures, alert a named owner, and test them when either side releases changes. Document what each integration does so it does not depend on one person's memory.

Should you build custom API integrations or use a platform?

Ready-made connectors and iPaaS tools are quick to set up and cover common patterns, such as syncing contacts between a CRM and an email platform. They suit standard, lower-volume flows where the logic is simple.

Custom integrations make sense when the logic is specific to your business, when volumes are high, when you need fine control over error handling and data mapping, or when the platform's connector does not support the objects you need. They take more effort to build and need someone to maintain them.

Many companies use both: platform connectors for simple flows and custom code for the integrations that carry core business data. The deciding factors are usually complexity, volume, how critical the data is, and who will look after the integration once it is live.

How does Vizio AI build API integrations?

API and systems integrations are a core capability of our DX Studio. We connect the CRM, finance, marketing, product and support tools a business already uses, so data moves between them reliably and each field has a clear owner. Integrations often feed a central data platform and the dashboards built on it, or trigger workflow automations downstream.

We document what each integration does, add monitoring and alerts, and support it after launch as vendors change their APIs. The starting point is mapping which systems hold which data today and where people are still copying it by hand.