Guest API POST /api/v2/conversations/messaging/contacts returns 401

Trying to send messages via the Guest API without the widget. I’m using POST /api/v2/conversations/messaging/contacts with a valid OAuth token. Getting a 401 Unauthorized error immediately.

{
 "message": "Unauthorized",
 "errors": ["Unauthorized"],
 "status": "401"
}

Token works fine for other v2 endpoints. Am I missing a specific scope for guest interactions?

The guest endpoint requires messaging:contact:write specifically. Standard read scopes won’t cut it. Check your token payload. Also, ensure the application has the Messaging capability enabled in Admin > Organization > Applications. Here’s the curl to verify your token scopes:

curl -X GET https://api.mypurecloud.com/api/v2/oauth/tokens/verify -H "Authorization: Bearer <TOKEN>"

Are you using the client credentials grant or authorization code flow for this token?

The docs state: “Client credentials tokens are restricted to service-to-service communication and cannot access guest endpoints.” You’ll need an authorization code grant with a user context.

’s spot on. Guest endpoints reject client credentials tokens outright, so you’ll need to switch to an authorization code flow or use a valid user context token instead.