---
title: "How can I deliver my own customer number for new contracts on signup?"
slug: "how-can-i-deliver-my-own-customer-number-for-new-contracts-on-signup"
updated: 2025-05-09T16:20:29Z
published: 2025-05-09T16:20:29Z
canonical: "help.frisbii.com/how-can-i-deliver-my-own-customer-number-for-new-contracts-on-signup"
---

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

# How can I deliver my own customer number for new contracts on signup?

For new registrations the customer data can be prefilled in the hosted order page or by subscriptionJS. If a customer number that has already been assigned is to be transferred with the registration of a customer, the field "Tag" can be used and prefilled. All fillable values are listed [here](https://docs.frisbii-transform.com/docs/hosted-customer-self-service) in the "Hosted Customer Self-Service" section.

The tag field is designed as a technical field and is used to temporarily store the customer number or an external ID, but not as its final storage location. This is done using the ExternalCustomerId field, which is also searchable.

The intermediate step above day is necessary because the ExternalCustomerId must be unique and this is also forced in the database. An ExternalCustomerId that is already stored in the system causes orders to fail.

In order to prevent failed orders, the ID can be transferred via the "tag" parameter and transferred to the ExternalCustomerId after a successful order. The "tag" parameter can be queried after ordering via **GET /api/v1/Customers/{id}**. However, it is not visible in the UI, therefore a storage in another field is necessary. You can use **PATCH /api/v1/Customers/{id}** to store the information in another field.

For more information, see the [Frisbii Transform REST API documentation](https://docs.frisbii-transform.com/reference/).