---
title: "Update Customer"
method: POST
path: "/tax/customers/{customer_id}"
---

# Update Customer

`POST /tax/customers/{customer_id}`

## Request

- Base URL: `https://api.numeralhq.com`
- URL: `https://api.numeralhq.com/tax/customers/{customer_id}`
- Auth: HTTP bearer

Update an existing customer's information. All fields are optional, but at least one must be provided. Only the fields you include are changed.

## Path parameters

- `customer_id` string, required

## Request body

- CustomerUpdateRequest: Request body for updating a customer. All fields are optional, but at least one must be provided.
  - `name` string: The customer's name
  - `email` string: The customer's email. Must be unique across your customers.
  - `is_tax_exempt` boolean: If true, all `POST /tax/calculations` sold to this customer will return $0 in tax owed.
  - `reference_customer_id` string: The ID of the customer in your system. Must be unique across your customers.

## Response `200`

The updated customer

- CustomerResponse
  - `id` string: The ID of the customer
  - `object` string: The type of object: `tax.customer`
  - `reference_customer_id` string: The ID of the customer in your system
  - `name` string: The name of the created customer
  - `email` string: The email of the created customer
  - `is_tax_exempt` boolean: If true, all `POST /tax/calculations` sold to this customer will return $0 in tax owed. The default value is `false`.

## Other responses

- `400`: Invalid request. Returned when no updatable field is provided (`INVALID_REQUEST`), the email is malformed (`INVALID_EMAIL`), the customer does not exist or has been deleted (`CUSTOMER_NOT_FOUND`), or another customer already uses the new `email` or `reference_customer_id` (`DUPLICATE_CUSTOMER`).

## Changes

- **2026-11-03** `f4650eaed11f`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/numeral-com/apis/numeral-api/changes/tax/customers/:customer_id/post.md)

---

[API](https://skmtc.dev/numeral-com/apis/numeral-api.md) - [All operations](https://skmtc.dev/numeral-com/apis/numeral-api/llms.txt) - [OpenAPI document](https://skmtc.dev/numeral-com/apis/numeral-api/revisions/f4650eaed11f?raw)