Documentation

Sending rules and limits

Current SMTP constraints and downstream Microsoft boundaries.

smtpify365 limits

These values describe the current implementation and can be configured operationally.

  • 25 MB message size by default
  • 100 envelope recipients
  • 30 connection attempts per minute per remote IP
  • 25 simultaneous clients per SMTP process
  • Envelope sender must match the connected mailbox

Microsoft limits still apply

Graph acceptance and Exchange Online delivery remain subject to current Microsoft mailbox, recipient, rate, anti-abuse, and service limits.