Create/Update Customer Contact API

6 min readGuide reference date: October 14, 2026.View original in Notion ↗

Purpose

This API creates or updates Sidetalk customer contacts using information collected by external service signup, reservation, or inquiry forms.

If the same memberId exists, it updates the existing customer. Otherwise, it creates a new customer.

URL

JavaScript

💡https://api.sidetalk.ai/v1/users

HTTP method

POST

Headers

Headers	Value	Description
Content-Type	application/json	Indicates that the request body is JSON.
Authorization	Bearer <api_key>	Use the API key provided in Install in the Sidetalk dashboard.

Body

Parameter	Type	Required	Description
userInfoId	Number/String	Conditionally required	The Sidetalk customer information ID, used to update an existing contact directly.
memberId	String	Conditionally required	The external service’s unique member ID. If the same memberId exists, the existing contact is updated.
sessionId	String	Conditionally required	The chat session ID, used to create/update contacts for non-member chat sessions.
userName	String	No	The customer’s name, saved as userName in Sidetalk customer information.
userEmail	String	No	The customer’s email, saved as userEmail in Sidetalk customer information.
userPhone	String	No	The customer’s phone number, saved as userPhone in Sidetalk customer information.
customerMemory	String	No	Customer notes.
extraFields	Object	No	Additional customer fields. Keys must match field keys in the dashboard’s Customer Information Settings.
customerAlias	String	No	A customer alias managed separately from userName. If omitted, the existing alias is retained.

At least one of userInfoId, memberId, or sessionId is required.

How to use extraFields

For additional fields created in Sidetalk Customer Information Settings, use each field key as the key in extraFields.

For example, if Customer Information Settings contains these fields:

Field name	Field key
Company name	company_name

Send the request body as follows.

JavaScript

{
  "extraFields": {
    "company_name": "코스모스팜"
  }
}

Example request

Create/update a member customer

Creates or updates customer contacts by memberId. Use for signup, synchronization of signed-in members, or external service member integration.

JavaScript

curl -X POST https://api.sidetalk.ai/v1/users \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer ${API_KEY}" \
  -d '{
      "memberId": "user_123",
      "userName": "홍길동",
      "userEmail": "hong@example.com",
      "customerAlias": "VIP 고객",
      "userPhone": "01012345678",
      "customerMemory": "VIP 고객",
      "extraFields": {
          "company_name": "코스모스팜"
      }
  }'

Create/update a non-member customer

Creates or updates contacts based on sessionId.

Use for customers without member IDs, such as chat sessions, guest reservations, or guest inquiry forms.

JavaScript

curl -X POST https://api.sidetalk.ai/v1/users \
-H "Content-Type: application/json" \
-H "Authorization: Bearer ${API_KEY}" \
-d '{
		"sessionId": "chat_session_abc123",
		"userName": "홍길동",
		"customerAlias": "VIP 고객",
		"userEmail": "hong@example.com",
		"userPhone": "01012345678",
		"customerMemory": "VIP 고객",
		"extraFields": {
		"company_name": "코스모스팜"
	}
}'

Directly update an existing customer contact

If you know the Sidetalk customer information ID, update directly using userInfoId.

JavaScript

curl -X POST https://api.sidetalk.ai/v1/users \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer ${API_KEY}" \
  -d '{
      "userInfoId": 123,
      "userName": "홍길동",
      "customerMemory": "상담 후 VIP 고객으로 변경"
  }'

Response body

JavaScript

{
  "success": true,
  "data": {
    "siteId": 1,
    "userInfoId": 123,
    "sessionId": "",
    "memberId": "user_123",
    "userName": "홍길동",
    "customerAlias": "VIP 고객",
    "userEmail": "hong@example.com",
    "userPhone": "821012345678",
    "userPhoneCountryCode": "82",
    "customerMemory": "{\"_sidetalk_customer_profile\":\"1\",\"memo\":\"VIP 고객\",\"extra_fields\":{\"company_name\":\"코스모스팜\"}}",
    "isManual": "1",
    "createdAt": "20260527143000",
    "updatedAt": "20260527143000"
  }
}

- userPhone may be normalized to digits when saved. Example: 01012345678 → 821012345678 - userPhoneCountryCode may also be saved. Example: 82

Response fields

Field	Type	Description
success	Boolean	Whether the request succeeded.
data	Object	The saved customer information.
data.userInfoId	Number	The Sidetalk customer information ID.
data.memberId	String	The requested external member ID.
data.sessionId	String	The linked chat session ID.
data.userName	String	The saved customer name.
data.userEmail	String	The saved customer email.
data.userPhone	String	The saved customer phone number.
data.customerMemory	String	Customer notes and additional field data.
data.userPhoneCountryCode	String	The saved phone country code.
data.isManual	String	Whether it was entered directly: 1 or 0.
data.createdAt	String	Creation date and time.
data.updatedAt	String	Modification date and time.

Error response

JavaScript

{
  "success": false,
  "error": "userInfoId, memberId, or sessionId is required."
}

JavaScript

{
  "success": false,
  "error": "At least one customer field is required."
}

JavaScript

{
  "success": false,
  "error": "Name must be at least 2 characters."
}

JavaScript

{
  "success": false,
  "error": "Invalid phone format."
}

Field	Type	Description
success	Boolean	Whether the request failed.
error	String	The error message.

Example image

Notes

Sending memberId and sessionId together can link CRM activities from a guest chat session to the memberId customer contact.
Contacts saved through this API are used as the customer reference for CRM activity history.
Contacts saved by an external API show an External API Integration history in Customer Contacts.
If the same userInfoId exists, updates that contact directly.
If the same sessionId exists, creates or updates the contact for that guest session.
The following aliases are also supported for backward compatibility and easier external integration.
customerAlias is stored separately from userName.
If customerAlias is omitted, the existing alias is unchanged.

Primary field	Supported aliases
userInfoId	user_info_id, id
memberId	member_id, wpUserId, wp_user_id, userId, user_id
sessionId	session_id
userName	user_name
userEmail	user_email
userPhone	user_phone
userPhoneCountryCode	user_phone_country_code
customerMemory	customer_memory
extraFields	extra_fields
isManual	is_manual
customerAlias	customer_alias