---
title: "Update a subscriber"
method: PUT
path: "/v4/subscribers/{id}"
tags: ["Subscribers"]
---

# Update a subscriber

`PUT /v4/subscribers/{id}`

If you include a custom field key that does not exist on your account, the request returns an error. Use [List custom fields](/api-reference/custom-fields/list-custom-fields) to retrieve existing keys, or [Create a custom field](/api-reference/custom-fields/create-a-custom-field) to add new fields before setting them for subscribers.<br/><br/><strong>NOTE:</strong> We support creating/updating a maximum of 140 custom fields at a time.

## Path parameters

- `id` integer, required

## Request body

- object
  - `first_name` string, nullable
  - `email_address` string, required
  - `fields` object — Custom field values keyed by the custom field's `key` (e.g. `last_name`, not `Last Name`). Unknown keys are ignored and reported in the response `warnings` array.

## Response `200`

Updates the subscriber's email address and first name

- object
  - `subscriber` object, required
    - `id` integer, required
    - `first_name` string, nullable, required
    - `email_address` string, required
    - `state` 'active' | 'cancelled' | 'bounced' | 'complained' | 'inactive', required
    - `created_at` string, required
    - `fields` object, required — Custom field values for the subscriber, keyed by the custom field's `key`.
  - `warnings` string[] — Present only when the request referenced custom field keys that don't exist on the account. Each entry names an unknown key that was ignored; the subscriber is still created or updated.

## Other responses

- `202` — Returns a 202 and asynchronously updates custom fields for the subscriber when more than 10 custom fields are included in the request
- `401` — Returns a 401 if the token and/or account cannot be authenticated
- `404` — Returns a 404 when the provided id does not exist
- `422` — Returns 422 with an error when email address is already in use

---

[API](https://skmtc.net/kit/apis/kit-api.md) · [All operations](https://skmtc.net/kit/apis/kit-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/kit/kit-api/revisions/0df0c90d12da/schema)