Message Size Limit

Stream, like most email systems, has a maximum message size that can be sent or received: 

• Outbound Email – 30MB, including attachments
• Inbound Email:
  • 40MB, including attachments - applies only when mail is ingested via forwarding rules
  • No limit - when mail is ingested via MS Graph API

Note: Message size, including file attachments, is limited to 22.5MB when composing to allow for any compression rules that may inflate the message above 40MB. An error will appear when the message exceeds 22.5MB.

Large Attachment Workflows

Adding Attachments

On outbound messages composed within Stream, the user will be prompted to automatically convert large file attachments into shareable links. When adding attachments that exceed the 22.5MB threshold, Stream will alert the user that the attachments will be converted to links. The user will then have the option to cancel and resize, or send as links.

All methods for adding attachments can be found in this knowledge article, Adding Attachments.

Note: Converting to links only applies to attachments and not large messages.