Setup
SMTP and IMAP: what are the differences?
SMTP sends mail. IMAP reads it. MAILTIG uses SMTP for campaign sends and optional IMAP so replies land in the workspace inbox.
By MAILTIG editorial. Reviewed by Engineering (Integration engineer) on 5 November 2026. Next review due 4 February 2027. 6 minute read.
Two protocols, two jobs. Mixing them up is how teams connect a mailbox, send a campaign, and never see the replies.
SMTP is for sending
Simple Mail Transfer Protocol is how a client hands a message to a server for delivery. MAILTIG stores SMTP host, port, username and password encrypted, tests the connection, and uses STARTTLS. The daily send limit still defaults to 50 for a personal mailbox.
SMTP alone does not collect replies. If you only configure SMTP, the mailbox is send-only.
IMAP is for reading
Internet Message Access Protocol lets a client list and fetch messages that already arrived. MAILTIG's optional IMAP settings poll the inbox (UID-aware, 25 messages per run) so replies can be matched to the contact and campaign.
Without IMAP, the person has to live in the provider inbox. MAILTIG will not invent a reply that it did not fetch.
What this is not
- Not Gmail or Microsoft 365 OAuth. Those use their own APIs. See the Gmail and Microsoft 365 guides.
- Not a prediction of inbox placement. A green SMTP test proves credentials and STARTTLS, not reputation.
- Not a shared inbox replacement unless IMAP is configured.
Connect SMTP when you have a mailbox that is not Gmail or Microsoft 365. Add IMAP if you want those replies in MAILTIG.