You should send API request depending on server your account is regitered at:
Web API UniOne allows you, not only to send emails lightning fast, but also to deal with unsubscribes, domains, separate projects or to get statistics with webhooks. You can browse all the methods in our Web API Reference.
All UniOne API methods require an HTTPS connection. UniOne accepts HTTP POST requests in JSON format up to 10 megabytes long and returns an HTTP response also in JSON. In case of error the JSON body with an error description and an API error code is returned, but you will also receive a corresponding HTTP return code. You can read more about error handling here.
You should send an API request to the server your account is registered at: