Best practices to follow when adding new contacts in the V3 API.

This topic documents the different ways you can create one or more contacts in an account. After creating new contacts, you can send them an Autoresponder Welcome Email or a Confirm Opt-in email. For details see Autoresponder and Confirmed Opt-in Emails.

Important

If specifying an email address

Only use this method when a contact gives you their explicit permission to send them an email. It is a violation of anti-spam and telemarketing laws, as well as a serious violation of the Constant Contact Terms of Service to use the Opt-in features of the API to opt a contact back in without his or her own action and consent.

If specifying an SMS number

Only use this method when a contact gives you their explicit permission to send them an SMS. It is a violation of anti-spam and telemarketing laws, as well as a serious violation of the Constant Contact Terms of Service to use the Opt-in features of the API to opt a contact back in without his or her own action and consent.

Create a Single New Contact

Make a POST call to the /contacts endpoint to create a single contact. Use this method for adding small numbers of contacts individually. For details, see Create a single contact.

When you make this POST request, Constant Contact checks to verify that the email address or SMS number provided in the request is unique in the user’s account. If the email address or SMS number already exists, Constant Contact returns a 409 conflict response code.

Create a New Contact or Update an Existing Contact

Make a POST call to the /contacts/sign_up_form endpoint to add a new contact to an account or update an existing contact based on their email address or SMS number. Only use this method when a contact gives you their explicit permission to send them emails. For details, see Create or Update a Contact.

Create Multiple Contacts with a Single API Call

You can import thousands of contacts in a single API call using either of the two Contacts Import endpoints. One endpoint supports a JSON payload, the other imports from a CSV file, learn more.