> ## Documentation Index
> Fetch the complete documentation index at: https://developer.chatsyncs.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Subscriber Update
> Update an existing subscriber's name, gender, or labels via the ChatSyncs API. Use when a developer asks how to keep subscriber profile data in sync with their own CRM.
Updates a subscriber's `first_name`, `last_name`, `gender` and labels.
**Fields you leave out are cleared, not kept.** `first_name`, `last_name` and `gender` are overwritten on every call:
send only `first_name` and the last name and gender are blanked (verified against the live API). Even a call with no
fields at all returns success and blanks all three. To change one field, read the subscriber with
[Subscriber Get](/developer-api/subscriber/get-subscriber) first and send all three back.
`label_ids` behaves differently: it only **adds** labels and never removes any, and an empty value changes nothing.
Use [Remove Labels](/developer-api/subscriber/remove-labels) to take one off. Give the ids as a comma-separated list,
e.g. `12,15`.
By REST convention this would ideally be a `PUT` request — but the ChatSyncs API only exposes
it as `POST`. Use POST as shown below.
**Where to find a label's ID:** open **Subscriber Manager → Labels** — the ID
is shown next to each label name, ready to copy. Or call
[Label List](/developer-api/label/list-labels) to fetch all of them at once. See
[Finding Your IDs & API Token](/developer-api/finding-ids#label-id-label_id) for a screenshot.
## OpenAPI
````yaml POST /whatsapp/subscriber/update
openapi: 3.1.0
info:
title: ChatSyncs Developer API
version: 1.0.0
description: >-
REST API for sending WhatsApp messages and managing subscribers through
ChatSyncs.
**Authentication.** Send your key as the `apiToken` parameter, or as
`Authorization: Bearer ` — both work on every endpoint **except Custom
Fields List**, which only accepts the `apiToken` parameter (a Bearer header
alone is answered with *The api token field is required.*). A wrong key
returns HTTP 401 `{"status":"0","message":"Unauthenticated."}`; no key at
all redirects to the login page.
**Methods.** Every endpoint accepts both GET and POST with the same
parameters, except Upload Media, which is POST-only. Use POST for anything
that changes data.
**Errors.** Failures usually come back as HTTP 200 with `"status":"0"` and
the reason in `message`, so always check `status`. `status` is the string
`"1"` or `"0"` on most endpoints and a boolean on a few.
**Lists.** Endpoints that return rows put them in `message` as a list; there
is no `data` field (Custom Fields List is the exception and uses `data`).
servers:
- url: https://platform.chatsyncs.com/api/v1
security: []
paths:
/whatsapp/subscriber/update:
post:
tags:
- Subscriber API
summary: Subscriber Update
description: >-
**Fields you leave out are cleared, not kept.** `first_name`,
`last_name` and `gender` are each overwritten on every call, so sending
only `first_name` blanks the last name and the gender (verified live).
To change one, read the subscriber with Subscriber Get first and send
all three back. `label_ids` is different: it only **adds** labels and
never removes any; use Remove Labels for that. A call with no fields at
all still returns success while blanking the name.
operationId: updateSubscriber
requestBody:
required: true
content:
application/x-www-form-urlencoded:
schema:
type: object
properties:
apiToken:
type: string
description: >-
Your ChatSyncs API key (not a WhatsApp/Meta access token).
[Where to find
it](/developer-api/finding-ids#api-token-apitoken).
example: API-KEY
phone_number_id:
type: string
description: >-
The WhatsApp account's phone number ID. [Where to find
it](/developer-api/finding-ids#phone-number-id-phone_number_id).
example: PHONE-NUMBER-ID
phone_number:
type: string
description: >-
The subscriber's phone number, with country code, digits
only.
example: PHONE-NUMBER
first_name:
type: string
description: The subscriber's first name.
example: Rahul
last_name:
type: string
description: The subscriber's last name.
example: Reddy
gender:
type: string
description: The subscriber's gender.
example: male
label_ids:
type: string
description: >-
Comma-separated label IDs, e.g. 1,4,5. [Where to find
it](/developer-api/finding-ids#label-id-label_id).
example: 1,4,5
required:
- apiToken
- phone_number_id
- phone_number
responses:
'200':
description: >-
Standard ChatSyncs response. `status` is `"1"` on success and `"0"`
on failure.
content:
application/json:
schema:
type: object
properties:
status:
type: string
description: '`"1"` = success, `"0"` = failure.'
message:
type: string
description: Human-readable result message.
examples:
success:
summary: Success
value:
status: '1'
message: Subscriber updated successfully
error:
summary: A required field is missing
value:
status: '0'
message: >-
The phone number id field is required., The phone number
field is required.
notFound:
summary: Unknown contact
value:
status: '0'
message: Subscriber not found
'401':
description: >-
`apiToken` is wrong. (With no token at all the API redirects to the
login page with HTTP 302 instead of returning JSON.)
content:
application/json:
schema:
type: object
properties:
status:
type: string
message:
type: string
examples:
unauthenticated:
summary: Wrong apiToken
value:
status: '0'
message: Unauthenticated.
````
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