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

# Integrations.

> How Charlie fits into a client's existing tech stack — and what it doesn't touch.

The most common technical question partners hear: *"What does this integrate with?"* This page gives you the answer.

## How routing happens.

Charlie runs as **Shopify Functions**, executing natively inside Shopify's infrastructure at checkout — before the order exists. This means:

* No ERP integration required (the order hasn't been created yet)
* No WMS connection needed (routing is decided before fulfillment begins)
* No latency added to checkout
* No impact on post-order workflows

```mermaid theme={null}
sequenceDiagram
    participant Customer
    participant Shopify as Shopify Checkout
    participant Charlie as Charlie OMS
    participant Payment as Payment Gateway

    Customer->>Shopify: Enters shipping address
    
    Shopify->>Charlie: Which locations can fulfill this order?
    Note right of Charlie: Apply constraints & preferences
    Charlie-->>Shopify: Return optimal locations
    
    Shopify->>Shopify: Calculate shipping options
    Shopify-->>Customer: Display available shipping methods
    
    Customer->>Payment: Complete payment
    Payment-->>Shopify: Order confirmed
```

Once an order is placed and routed, it flows into Shopify's standard fulfillment process — which connects to whatever the client already uses (ERP, WMS, 3PL, carrier) without any changes.

## What Charlie doesn't replace.

Charlie doesn't integrate with ERPs — intentionally. It leverages Shopify's existing interfaces, so the client's ERP continues to receive orders exactly as before. Nothing changes downstream.

| System                 | Charlie's relationship                                     |
| ---------------------- | ---------------------------------------------------------- |
| ERP (SAP, Cegid, etc.) | Untouched — order flows in as normal post-routing          |
| WMS                    | Untouched — fulfillment execution is unchanged             |
| 3PL                    | Untouched — carrier and shipment logic unchanged           |
| Shopify POS            | Enhanced — safety stock visibility and revenue attribution |
| Shopify admin          | Enhanced — Charlie lives inside it, no second screen       |

## On inventory integrations.

Charlie's safety stock feature works with Shopify's native inventory. For clients using third-party tools that also read Shopify's native stock (e.g. a storefront app, a B2B portal, a POS extension), a proper safety stock setup requires that those tools also respect sellable inventory — not just raw available stock.

Charlie doesn't currently have native integrations with these tools, but is actively building them. Ask the Charlie team for the current status if a specific tool is relevant for your client.

## IS/IT impact.

<CardGroup cols={2}>
  <Card title="Zero IT burden" icon="check">
    No integration requirements, no ongoing maintenance, no version conflicts.
  </Card>

  <Card title="Auto-evolving" icon="arrows-rotate">
    Charlie updates automatically with Shopify — no deployment needed.
  </Card>

  <Card title="Clean uninstall" icon="trash">
    All data stored in Shopify metafields. Remove the app without data loss or migration.
  </Card>

  <Card title="No ERP integration" icon="plug">
    Routing happens before orders are created — the ERP never needs to know Charlie exists.
  </Card>
</CardGroup>

## The one integration that requires dev work.

Charlie's safety stock feature can display accurate sellable inventory on the client's storefront. This requires a **front-end theme integration** — a few days of development work.

This is the only touch point that involves your agency's dev team.

<Card title="Custom development." icon="arrow-right" href="/technical/custom-development" horizontal>
  See exactly what the theme integration involves and how to scope it.
</Card>