---
title: "Checkout: integration"
canonical: "https://ingrid-support.refined.site/space/KB/11534561/Checkout%3A%20integration"
format: markdown
---
Integration is phase 3 of your [Checkout implementation](https://support.ingrid.com/space/KB/11501718/Checkout+implementation). **You lead it** — we guide with documentation and our integrations team.

> ℹ️ This page explains **what has to happen, who needs to be involved, and what you have to decide**. Your developers will want [developer.ingrid.com](https://developer.ingrid.com) for endpoints, payloads, and code.

## What integration actually involves

Adding Ingrid itself is usually straightforward. What needs planning is **how data flows between Ingrid and the rest of your systems** — and that is a decision about your architecture, not about Ingrid.

![image](media://af79f3af-bdff-4071-a557-676cdbff9041)

Your own stack may have more systems or fewer, connected differently. The shape of the problem is the same.

## Connecting Checkout to your storefront

Your e-commerce platform fetches the Ingrid widget and places it in the checkout. From then on:

- your platform keeps Ingrid updated with cart contents and customer information
- the widget talks to Ingrid so the shopper sees the right delivery options

On a standard platform, a [plugin](https://support.ingrid.com/space/KB/11501969/Ingrid+e-commerce+plugins) does this for you. On a custom or headless storefront, your developers build it against our API.

## The transport order, and why it matters

When a purchase completes, Ingrid creates a **transport order** containing everything needed to book a shipment. Each one has a unique identifier, the **TOS ID**, and the full transport order can be retrieved from Ingrid at any time using it.

You can view and create transport orders in the Ingrid Merchant Platform in either environment.

## The decision you need to make

Your booking system — Ingrid Transport or another vendor's — needs the transport data produced at checkout. There are two ways to get it there, and this is worth deciding deliberately because it changes how much work your ERP team has.

### Option A: pass all the required data through your systems

The classic approach: move every required field through the intermediary systems, usually ERP and WMS.

**Simple to understand, but:**

- you have to know up front which data points booking requires
- if those requirements change — adding support for add-ons, for example — your ERP may need updating too
- your ERP has to carry and handle the data

### Option B: pass only the TOS ID

Move just the identifier. Any system holding valid credentials can then fetch the full transport order from Ingrid itself. In practice the TOS ID travels through the ERP, and the WMS fetches what it needs directly.

**Benefits:**

- a much smaller integration surface toward your ERP
- when booking requirements change, intermediate systems do not need updating

Which fits depends on your existing setup. Scope it with your implementation consultant during the planning workshop — it is a good example of something far cheaper to decide in phase 1 than to rework in phase 4.

## Connecting your WMS

Before your warehouse team starts, make sure they have credentials for the correct merchant *and* the correct environment. Staging and production credentials are not interchangeable.

![image](media://907bcb15-c8ca-4c25-9bba-b57005a4a878)

Your WMS retrieves transport order data from Ingrid using the TOS ID. Because a transport order can be reopened more than once, a request returns a list of results with the most recent first — so the first result is always the current state. Your developers will find the request format, authentication, and full field reference in the [developer documentation](https://developer.ingrid.com).

If Ingrid Transport is your booking system, a booking needs only the TOS ID and the number of parcels.

## Who you need for this phase

Your technical lead owns this work, and needs to be available weekly rather than occasionally. Where your WMS, ERP, or OMS is involved, those owners need to be in the conversation from the start — integration delays are far more often about availability than about difficulty.

## Next

[Phase 4–5: Checkout testing and go-live →](https://support.ingrid.com/space/KB/11469099/Checkout+testing+go-live)