Before you buy

Can Microsoft 365 handle this without SMTPReady?

Start with Microsoft. If your device or app can use a supported Microsoft 365 method directly, you probably do not need SMTPReady. Add SMTPReady only when those methods do not meet your requirements and Microsoft 365 must remain the outbound tenant.

Microsoft-native routes

Start with Microsoft.

Microsoft documents four ways for devices and applications to send mail. Use one directly when it meets your requirements; check Microsoft’s current documentation for the latest limits.

MethodWorks whenMain constraintDecision

Client SMTP submission (OAuth)Your sender can do modern OAuth and TLS.The device/app must implement OAuth; a mailbox is used to send.Use Microsoft directly →

SMTP relayYou can meet connector requirements and send through port 25.Typically needs a certificate or static public IP visible to Microsoft.Use Microsoft directly →

Direct SendYou only need the scenarios Microsoft supports and can operate the sender as an internet mail source.Microsoft recommends it only for advanced customers; it has narrower delivery semantics.Use only if it matches the workload →

High Volume EmailYour traffic is internal and the service's current constraints match the workload.Different endpoint/account model; not a general replacement for all external mail.Use if its requirements match →

Microsoft: send mail from multifunction devices and applications ↗

Sender supports SMTP only+Microsoft 365 must remain the outbound tenant+No Microsoft-native method works=SMTPReady bridges the gap

When SMTPReady is useful

Keep SMTP local. Modernize the Microsoft side.

The sender talks SMTP only to a Windows host you control. SMTPReady queues locally and handles Microsoft authorization and delivery from there.

Review security Buy SMTPReady →

Not sure?

Send us the device model and current settings.

We can help you rule out the simpler Microsoft-native route first. Include the current SMTP target, whether recipients are internal or external, and what is failing or changing. No sales call.

Email support →