---
title: Creating a Customer
slug: devdocs/creating-a-customer
docTags: 
createdAt: 2026-10-16T12:03:51.992Z
---

Use the `customer.create` mutation to create a customer.

:::BlockQuote
⚠️ **WARNING**
Search first. Run **Customer Identification** with the phone number and create the customer only when no customer matches. A duplicate splits the history of the same person.
:::

**Query**

```graphql
mutation CreateCustomer($payload: CustomerCreateInputType!) {
  customer {
    create(payload: $payload) {
      result {
        publicKey
        firstName
        lastName
        active
        mobilePhone
        category { publicKey name active }
      }
      errorCode
      errorMessage
      errorData
    }
  }
}
```

**Variables**

```json
{
  "payload": {
    "category": "<customer category key>",
    "firstName": "Jane",
    "lastName": "Doe",
    "mobilePhone": "0700000001"
  }
}
```

**cURL**

```bash
curl --location 'https://sandbox.expressoft.eu/connect/api/interopgql' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer <token>' \
--data '{"query": "mutation CreateCustomer($payload: CustomerCreateInputType!) { customer { create(payload: $payload) { result { publicKey firstName lastName active mobilePhone category { publicKey name active } } errorCode errorMessage errorData } } }", "variables": {"payload": {"category": "<customer category key>", "firstName": "Jane", "lastName": "Doe", "mobilePhone": "0700000001"}}}'
```

**Response**

```json
{
  "data": {
    "customer": {
      "create": {
        "result": {
          "publicKey": "00000000-0000-0000-0000-000000000001",
          "firstName": "Jane",
          "lastName": "Doe",
          "active": true,
          "mobilePhone": "0700000001",
          "category": {
            "publicKey": "00000000-0000-0000-0000-000000000010",
            "name": "Gold customers",
            "active": true
          }
        },
        "errorCode": null,
        "errorMessage": null,
        "errorData": null
      }
    }
  }
}
```

Take `category` from the customer categories (see **Customer Identification**). Keep the `publicKey` of the new customer.

## Fields of a customer

| Field         | Type       | Required | Default | Description                        |
| ------------- | ---------- | -------- | ------- | ---------------------------------- |
| `category`    | `Guid!`    | yes      |         | Customer category key.             |
| `firstName`   | `String!`  | yes      |         | Customer first name.               |
| `lastName`    | `String!`  | yes      |         | Customer last name.                |
| `code`        | `String`   | no       |         | Customer code/reference.           |
| `email`       | `String`   | no       |         | Customer email.                    |
| `mobilePhone` | `String!`  | yes      |         | Mobile phone (mandatory).          |
| `workPhone`   | `String`   | no       |         | Work phone.                        |
| `homePhone`   | `String`   | no       |         | Home phone.                        |
| `birthDate`   | `DateTime` | no       |         | Customer date of birth (optional). |

## Add an address

An address needs a street. Get the street key from the **Setup Queries** of the Delivery API (**Get Streets by County**), then use `customer.createAddress`. See **Editing a Customer**.

:::BlockQuote
ℹ️ **INFO**
The error codes of `customer.create` are `InvalidCustomerCategory` (2) and `InvalidEmailFormat` (4). The full list is in **Errors & Troubleshooting**.
:::