Can I develop a Flutter mail app for Microsoft Exchange using only SMTP?

Question

I want to develop a Flutter-based email client for my company that allows users to consult (receive) and send emails. However, my company uses Microsoft Exchange (currently are using Outlook in phones, but due to some local politics it will be eliminated) they are allowing only SMTP for sending emails—no IMAP, POP3.

Is it possible to build a full email client in Flutter using only SMTP? If SMTP is only for sending emails, how can I retrieve (consult) emails from Microsoft Exchange? Are there any Flutter plugins or workarounds that support Microsoft Exchange when IMAP/POP3 are not allowed? Any guidance, recommended libraries, or alternative solutions would be greatly appreciated!

Answer 1

No, you cannot develop a full-featured Flutter mail app for Microsoft Exchange using only SMTP because SMTP (Simple Mail Transfer Protocol) is designed only for sending emails, not for receiving or managing them.

To build a complete email client for Microsoft Exchange, you need:

1. SMTP (for sending emails)

   • Yes, you can use SMTP(via smtp.office365.com for Office 365/Exchange Online).

2. IMAP or POP3 (for receiving emails) – Not ideal for Exchang

   • Microsoft does not support IMAP/POP3 for modern Exchange Online accounts with security policies.

3.Microsoft Graph API (Recommended for Exchange & Office 365)

• The best way to interact with Microsoft Exchange is via **Microsoft Graph API
• It provides access to **emails, contacts, calendars, attachments, and more
• Requires OAuth 2.0 authentication.

How to proceed? If you're building a Flutter email app for Microsoft Exchange, you should:

• Use SMTP for sending emails.
• Use Microsoft Graph API for fetching, reading, and managing emails.
• Implement OAuth 2.0 for authentication (Microsoft does not allow basic authentication for security reasons).