Building apps
What is API integration?
API integration is connecting your application to another piece of software through its API, so the two exchange data and trigger actions in each other without anyone copying information between them.
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Technical definition
An API integration is an implemented connection between systems using a published interface. Building one involves authenticating to the provider, usually with an API key or an OAuth token, calling documented endpoints, handling the response format, managing rate limits, and dealing with errors and retries.
Integrations run in two directions. Your application calls out to request data or cause an action. The other system calls back through a webhook when something happens on its side.
In plain terms
An API integration is a connection between two pieces of software so they talk to each other directly.
Every time someone exports a spreadsheet from one system to import into another, that is an integration that does not exist yet.
Why it matters
Manual data transfer between systems is where small businesses lose hours and introduce errors. Bookings retyped into the calendar, invoices copied into the accounting system, leads pasted from the form into the CRM. Each one is a task that runs forever and gets skipped when things are busy.
An integration removes the task rather than speeding it up.
What to expect before you build one. The API key is a credential, so it belongs in server-side storage, never in browser code. Rate limits mean you cannot call as often as you like. External systems fail, so anything important needs a retry and a record of what happened. And APIs change, so an integration is something you maintain rather than something you finish.
