Use case
An email follow-up tracker that shows who is waiting on you
Replies rarely get missed because you forgot to care. They get missed because a newer email pushed them out of sight. PlainMailOS reads your incoming mail, spots the messages that are waiting on you, and tracks how long they have waited, so nothing important goes quiet.
Why replies disappear under newer email
Important emails do not announce themselves. You read a message, decide to answer it properly later, and by the afternoon it has scrolled below a dozen newer ones. Nothing marks it as unfinished, so it simply stops existing until the sender chases you.
Most follow-up tools ask you to fix this by hand: star the message, set a reminder, add a label. That works only if you remember to do it at the exact moment you are least likely to.
- A client asks for a revised proposal by Friday and the thread goes quiet.
- A question about an invoice sits unanswered for a week.
- A colleague is waiting on a decision only you can make.
How PlainMailOS tracks what is waiting on you
PlainMailOS classifies every incoming message with a fixed set of rules. For replies it looks for signals such as a direct question, an explicit request for a response, and deadline-shaped language. A message that scores strongly is filed under Needs reply and added to your Waiting list.
Each waiting item shows how long it has been waiting. As the time grows, an item moves from within its window to flagged, and then to escalated, so the oldest and most overdue messages are impossible to overlook.
- Needs reply: messages that ask you something or expect a response.
- Waiting: everything currently waiting on you, with its age.
- Follow-ups and alerts: escalation as an item ages.
Rules you can read, not a black box
Every classification comes with a plain-English reason, for example: an explicit response request was detected, a direct question was detected, and deadline-shaped language was detected. You can see exactly why a message was filed the way it was.
The rules are deterministic. The same email always gets the same answer, which makes the system predictable and easy to trust or correct.
What you need to get started
Create an account and connect a Microsoft 365 (work or school) or IMAP mailbox. Gmail support is coming soon. PlainMailOS then works through your existing mail, so there is nothing to migrate.
Questions
Does PlainMailOS send follow-up emails for me?+
Which email accounts does it work with?+
How is this different from starring or flagging emails?+
Can a team use it?+
Stop chasing your own inbox
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Last reviewed 2026-10-04.