Prepare an SMTP2GO sender and application credential
Verify the SMTP2GO sending identity and distinguish API keys from SMTP users before connecting an application.
Reviewed
SMTP2GO provides an outbound SMTP relay and email API. Its webhook feedback describes mail you sent; it is not a mailbox that automatically receives replies for the From address.
Prepare the outgoing identity
- Verify your sender/domain using the current getting-started guide.
- Choose API integration or authenticated SMTP relay and create the corresponding credential.
- Scope permitted senders/recipients and account controls to the application’s intended use.
- Keep API keys and SMTP credentials separate in backend secret configuration.
Domain authentication records should not replace MX records used by the organization’s mailbox provider. Decide where replies go and who receives them before testing production mail.
Verify the intended access
Run a controlled single-recipient send and inspect SMTP2GO activity. For API sends, check both request status and the returned result/failure details. For SMTP, confirm TLS and authentication without weakening certificate validation.
If a message is rejected, inspect sender verification, account restrictions, and the selected credential type. Do not create a broader account credential merely to work around a permission error.
MailKite can receive replies on a separate verified application address while SMTP2GO remains the outgoing relay. That is an explicit two-service design; delivery-event webhooks alone do not supply incoming email bodies.