This endpoint will add a customer to a list, or if the customer already exists, will update the record of that customer with the supplied data.

POST /lists/LIST_ID/contacts/

Payload Specification

Param NameRequiredTypeDescription
emailYesStringThe email address of the customer
first_nameNoStringThe first name of the customer
last_nameNoStringThe last name of the customer
phoneNoStringA phone number for the customer.
timezoneNoStringTimezone of customer, should be in list of TZ database names
ageNoNumberAge of customer
genderNo"m" or "f"Gender of customer.
languageNoStringTwo letter code of customers language
address1NoStringFirst line of address for customer
address2NoStringSecond line of address for customer
cityNoStringCity where customer lives.
stateNoStringState where customer lives.
postal_codeNoStringPostal code of customer's address
countryNoStringCountry where customer lives
birthdateNoStringISO formated date when the customer was born.


Any additional params will be treated as strings and added to the custom_fields of the list contact.


All specified parameters will update the customer's record for all applications within Rejoiner, not just for the given list.

  "email": "[email protected]",
  "first_name": "Test",
  "age": "28",
  "another_custom_field": "abc"

On a successful request, the response will return a structured response representing the entire list contact.

  "customer": {
    "id": "CUSTOMER_ID",
    "email": "[email protected]",
    "first_name": "Test"
  "custom_fields": {
    "existing_custom_field": "xyz",
    "another_custom_field": "abc"

Newly added contacts will return a successful response with status code 201.

If the contact is already on the list a successful response with status code 200 will be returned.