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

# Create Customer

Upsert a customer record. If a customer with the given `external_id` already exists, their name and email are updated; otherwise a new customer is created.

**Auth:** `sk_` (secret key) only.

<ParamField body="external_id" type="string" required>
  Your unique identifier for this customer. Used for upsert matching.
</ParamField>

<ParamField body="name" type="string">
  Customer display name.
</ParamField>

<ParamField body="email" type="string">
  Customer email address.
</ParamField>

### Response

<ResponseField name="external_id" type="string" required>
  The customer's external identifier.
</ResponseField>

<ResponseField name="name" type="string">
  Customer display name.
</ResponseField>

<ResponseField name="email" type="string">
  Customer email address.
</ResponseField>