OverviewWhat is SMTP relay?
An SMTP relay is a mail server that accepts messages from your application over the standard SMTP protocol and delivers them to recipients' mailbox providers on your behalf. Your app authenticates, hands off the message and moves on. MigoSMTP runs the relay on MigoMTA, so we handle queuing, retries, authentication signing and provider-specific throttling instead of you running and tuning your own mail server. You keep your existing code and libraries and change only the host, port and credentials.
Anything that can speak SMTP can use the relay: web frameworks, CMS plugins, ticketing and billing tools, scripts, printers and scanners. Each app, environment or client gets its own SMTP account with separate credentials, sending limits and an optional IP allowlist, so you can rotate or disable one without touching the rest. TLS is required on every connection. Per-account limits stop one misbehaving app from using up your quota, and usage reports show which account sent what.
A relay matters for deliverability because mailbox providers judge the sending infrastructure as much as the content. A managed relay signs mail with your domain's DKIM key, applies consistent authentication, slows down when a provider defers, retries temporary failures and suppresses addresses that bounce or complain. When something does go wrong, the message log shows the raw SMTP responses and our AI assistant explains them in plain language, so your team and your support desk can see what happened and what to change.