A shared inbox fails in small ways that nobody sees at the time. A message two people answered, a message nobody answered, a promise made in March that nobody wrote down. The twelve rules below each name the failure they prevent and the setting that enforces them, in Gmail, in Outlook, or in a shared inbox tool.
Nothing here needs a purchase to start. The free versions use Google Groups Collaborative Inbox, Gmail delegation and Microsoft 365 shared mailboxes, with menu paths checked against Google's and Microsoft's help pages in October 2026. We build Sektra, a shared inbox tool, and it appears once, at the end.
Give every message one owner. Keep three states and name them. Settle who replies before anyone types. Keep notes on the thread. Reply from the shared address. Let rules do the first sort. Measure response time as a percentile. Write promises down with a date. Snooze with a date. Prune members monthly. Template the repeat answers and edit each one. Look at the oldest open thread every week.
What are the best practices for a shared inbox?
The rules fall into four groups: ownership, state, context and measurement. The first six stop mail falling between people. The next three keep the record honest. The last three keep the inbox healthy over months. Each rule below ends with where the setting lives.
1. Every message has exactly one owner
An unowned message gets two replies or none. Assignment is the fix, and it has to be visible to everyone on the thread itself. In a Google Groups Collaborative Inbox, members with the Who can moderate metadata permission click Take or Assign. A Microsoft 365 shared mailbox has no assignment; teams use a category per person, which works until two people categorize at once. A shared inbox tool assigns by hand or by rule.
2. Keep three states and name them
Open, waiting on them, done. More states than that and people stop applying them. In Collaborative Inbox the states are Mark as complete and No action needed, with Is unresolved as the filter. In Gmail delegation, use three labels on the shared account and nothing else. In Outlook, three categories on the shared mailbox. In a tool, the states are built in and a thread cannot be in two at once.
3. Settle who is replying before anyone types
Gmail and Outlook show nothing when a colleague is drafting in the same thread. The free convention is assign first, draft second, and it holds for a team of three in one room. Past that, a typing indicator on the thread is the only version that works, because it asks nobody to remember anything. How to stop two people replying to the same email covers both.
4. Keep the discussion on the thread
A forward to a colleague asking what to say leaves the shared address, and the answer lives in two personal mailboxes. Internal notes keep it beside the client's message. Collaborative Inbox has only the note in the assignment email, and Gmail delegation and Outlook shared mailboxes have none. A tool with notes and mentions is the setting here; until then, keep the discussion in one chat channel per inbox and link the thread.
5. Reply from the shared address
A client who replies to a person's address takes the thread out of the shared inbox, and it leaves with that person. In Outlook, an admin grants Send As or Send on Behalf under Manage mailbox delegation in the Exchange admin center. The From field then offers the shared address when you reply.
In Gmail, the Who can post as group permission lets a member send from the group address, and Send mail as under Settings, Accounts and Import adds an alias. A tool sends from the connected address by default.
6. Let rules do the first sort
Sorting by hand is unowned work, so it happens late or never. Gmail filters on the receiving account can label and skip the inbox. Outlook on the web rules live under Settings, Mail, Rules, Add new rule, and Stop processing more rules is on by default, so order them. A tool's assignment rules go further: by sender, by domain, by intent tag, round robin or to whoever has the least open.
7. Measure response time as a percentile
An average response time of four hours hides the client who waited a week. The median and the ninetieth percentile do not. Gmail and Outlook measure nothing. A tool reports response and resolution time per teammate, per inbox and per client. How Sektra calculates analytics describes one method, and it is a fair test for any vendor. Reply speed is the wrong metric for account teams argues for what to measure alongside it.
8. Write down what was promised, with a date
The promise lives in paragraph three of a reply that nobody will reread. Pull it out. In Gmail, star the thread and snooze it to the date. In Outlook, flag it with a reminder date. In a tool, a record of commitments per client with a deadline on each, as tracking commitments in email describes. The test is whether someone new to the account can see the open promises in one place.
9. Snooze with a date, and only with a date
Parking a thread with no return date is deleting it slowly. Gmail snooze and Outlook flags with reminders both carry a date. A tool's snooze should also wake the thread early when the client replies first, so a parked thread never means a client waiting for a reply that is already overdue.
10. Review members every month
Leavers keep access until someone removes them, and in a shared login they keep it until the password changes. In Outlook, the member list is in the admin center under Teams and groups, Shared mailboxes. In Gmail, the delegate list is under Settings, Accounts and Import, Grant access to your account, and a Google Group's members are in the group itself. In a tool, seats. Put it on the first of the month.
11. Template the repeat answers, and edit every one
The same five questions arrive every week. A template saves the retyping; the edit keeps the client from noticing. In Outlook, a draft saved from Message, Mail template, Save email as template is listed under Settings, Mail, Templates. The My Templates pane on the Message tab holds shorter snippets. Gmail has a Templates feature as well. In a tool, shared templates and assistant drafts that quote the thread, with a person deciding to send.
12. Look at the oldest open thread every week
The number to watch is the age of the oldest open thread. Once a week, sort open threads by received date and read the oldest one aloud. In Collaborative Inbox that is the Is unresolved filter; in Outlook, sort the shared mailbox by received; in a tool, the oldest open view or the morning digest. If the oldest thread is older than your stated response time, that is the week's first job.
Where a tool replaces the conventions
We build Sektra, and the twelve rules describe its shape. It is a separate workspace that syncs two-way with Gmail, Outlook, IMAP and WhatsApp Business. Gmail and Outlook connect through Google or Microsoft sign-in, so Sektra never sees those passwords. Mail stays where it is, and a teammate still in plain Gmail or Outlook sees the same threads.
Rules one to six are settings. Assignment by rule, three states with snooze, notes and mentions on the thread, sending from the connected address, and routing by intent tag or round robin. The typing indicator reads A teammate is typing a reply. Rule seven is analytics as percentiles per teammate, inbox and client.
Rules eight and nine are the memory layer, a record per client of what was promised in either direction with dates, and what they asked that has no answer yet. Snooze stands down when the client replies first. Rule twelve is the morning digest, which lists what you owe and who owes you.
A legal or accounting practice running one clients@ address gets all twelve without writing a convention down. The product page describes each part, and the Outlook integration page covers shared mailboxes, categories and flags.
