IMAP and POP3
Collecting mail uses one of two protocols, and the difference is more consequential than it appears.
Where to find it
Architect Panel → Integration & Connections:
- E-mail Accounts — the accounts mail is sent and received through
Architect Panel → Integration & Connections:
- E-mail Inboxes — the inbox doing the collecting
The essential difference
- IMAP leaves mail on the server and syncs state. Several things can look at the same mailbox and agree about what has been read.
- POP3 downloads mail, typically removing it from the server.
Prefer IMAP
Because POP3's behaviour is destructive by default. If the platform collects by POP3 and removes messages, anybody else looking at that mailbox — a person, a backup, another system — finds them gone.
That is discovered at the worst moment: somebody goes looking for an e-mail they know arrived and it is not there.
Where POP3 still fits
A mailbox that exists solely for the platform, where removing collected mail is exactly what you want and nobody else will ever look. That is a legitimate arrangement and it should be a deliberate one.
Encrypt
The same as sending. Unencrypted collection sends credentials and message content in clear text.
Know what happens after collection
The setting that causes most surprises. Are messages left, marked read, moved, or deleted?
Whichever you choose, make sure it is a decision. "We did not realise it was deleting them" is a conversation that happens after something has been lost, and there is rarely a way back.
Do not collect from somebody’s mailbox
A person's inbox and an automated collector will interfere with each other, and the person will lose mail. Use a dedicated mailbox.
Watch the mailbox size
With IMAP leaving everything in place, a busy mailbox grows indefinitely and will eventually hit a quota — at which point new mail bounces and you stop receiving enquiries.
Have a plan: archive, move processed mail to a folder, or apply a retention policy at the provider.
Microsoft 365 again
As with sending, Graph is generally the better route where available, and organisations disabling basic authentication will break IMAP collection without warning you.
Worked example
A support mailbox is collected by IMAP with processed messages moved to a folder rather than deleted, so the mailbox stays a manageable size and nothing is destroyed. A retention policy at the provider clears the folder after a year, and the records created from those messages are the permanent copy.
Recommendations
- Prefer IMAP — POP3 is destructive by default.
- Decide what happens after collection, deliberately.
- Use a dedicated mailbox, never a person’s.
- Plan for mailbox growth before it hits a quota.