I'm using /:id/managecontact
endpoint to add new emails to list. Emails is added but no confirmation/opt-in email is being sent to that email.
Is it not posible to do that with API calls or there has to be made some additional call ?
When adding contacts directly through the API, the email address is directly inserted in the list, without confirmation email. To generate an opt-in message, you should use the subscription widget -> https://www.mailjet.com/docs/widget
Feel free to open a support ticket, should you have additional questions.