# What is API – Application Programming Interface?

What is API – Application Programming Interface? A 'language' for communication between systems.

## How it works in practice

The API is the glue of your tech stack. A new order automatically flows to Klaviyo, to the 3PL, and to GA4. Without an API, every system is isolated and requires manual export/import.

## Related metrics

- Webhook — a notification sent when an event occurs
- Integration — connecting systems via API
- Automation — API enables automation
- Headless Commerce — fully API-based

## Common misconception

'API is a developer-only concern.' A store owner should understand what an API can do. 'A Shopify order should open a ticket in Zendesk' — every platform supports this.

## How to fix it

Integration not working? (1) API key — expired? correct permissions? (2) rate limit — the allowed number of requests, (3) review the integration's error logs, (4) contact support with the exact error message.

## Real-world example

A store using Shopify + Klaviyo + a 3PL + Zendesk: everything was manual, taking hours daily. With API integration: an order automatically flows to the 3PL, Klaviyo, and Zendesk. Savings of 4 hours/day, worth about $3,300/month.

## Where to start

Map your tech stack and every manual process. Any process repeated 10+ times a day is a candidate for API integration. No-code tools: Zapier, Make.

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Category: Technology · From the [Jimmy OS KPI Glossary](https://jimmy-os.com/glossary/kpi.md) · Source page: https://jimmy-os.com/glossary/kpi/api-application-programming-interface