> ## Documentation Index
> Fetch the complete documentation index at: https://docs.clearline.me/llms.txt
> Use this file to discover all available pages before exploring further.

# Checkout Integration App

## Overview

The Checkout Integration app is when ClearLine is integrated into the POS System Checkout Flow, proposing to show marketing actions to Merchant or automatically showing them via POS Rules to Customer after the Purchase.

## Checkout Integration Flows:

<CardGroup cols={2}>
  <Card title="Manual Flow in POS System Checkout (CMC)" icon="hand" href="/integration-options/checkout-integration-app/manual-flow-in-pos-system-checkout-cmc">
    API flow for retrieving widgets, initiating sessions, and displaying QR codes on CFS or via email/SMS.
  </Card>

  <Card title="POS Integration: CFS – Web API Events (Iframe postMessage)" icon="code" href="/integration-options/checkout-integration-app/pos-integration-cfs-web-api-events-iframe-postmessage">
    JavaScript iframe communication between CFS/Pages and POS systems using window\.postMessage() events.
  </Card>

  <Card title="Checkout Integration Flow Example" icon="diagram-project" href="/integration-options/checkout-integration-app/checkout-integration-flow-example">
    Complete checkout flow example with coupons, transactions, and marketing triggers (manual or automated).
  </Card>

  <Card title="Automated flow in POS System Checkout" icon="robot" href="/integration-options/checkout-integration-app/automated-flow-in-pos-system-checkout">
    Fully automated integration where widget sessions are triggered in real-time based on transaction events.
  </Card>

  <Card title="CFS Carousel" icon="images" href="/integration-options/checkout-integration-app/cfs-carousel">
    Retrieve carousel URL displaying marketing slides on Customer Facing Screen using pre-defined templates.
  </Card>
</CardGroup>