Shared Mailbox vs Distribution List vs Group: Which to Use

Three things get called the same thing in most companies: the "team email," the "group inbox," the "distro list." They are three different mechanisms. They store mail differently, they route mail differently, and they answer the question "who replied to that?" in three different ways. Picking the wrong one is why sales@ keeps missing leads, why the on-call rota is invisible on Monday, and why five people just answered the same customer.

The distinction that decides everything is where the message physically lives after it is delivered. A shared mailbox has one store, and every reply is sent as the shared address. A distribution list has no store — the server fans the message out into each member's personal mailbox, and their replies come from them, not the list. A group is a hybrid: it keeps its own archive and can also fan out. Once you see the message-store split, the rest follows.

This post separates the three mechanisms, tells you which behaviours are Microsoft 365-specific and which are Google Workspace-specific, and points to the vendor page you should verify licensing and size limits on before you commit. Product prices move; the mechanics do not.

The verdict up front#

If a team of people needs to work the same queue of incoming mail — support@, billing@, orders@ — and reply as that address so the customer sees one voice, use a shared mailbox. It is the only one of the three that gives you a common Sent folder and a common history of what has been answered.

If a single sender needs to reach a group of people whose replies should come from themselves, not from the group — an announcements@ list, a team@ paging alias, a customers-of-plan-x newsletter — use a distribution list. Its whole job is fan-out. It does not remember anything, and that is a feature, not a bug.

If you want both — a place where the team can post and everyone sees the thread, plus optionally have the mail land in personal mailboxes — use a group. In Microsoft 365 that is a Microsoft 365 Group; in Google Workspace it is a Google Group, and if you also need assignment and resolution tracking, turn on Collaborative Inbox on that group.

The most common wrong pick is choosing a distribution list for what should be a shared mailbox. The list works for the first month because everyone can see the mail. Then two people reply, one archives without answering, and nobody can tell what state a customer thread is in — because there is no shared state to look at. If you need answered/unanswered, use a shared mailbox or a group.

At a glance#

The table below is the shortest honest summary. Read it in the order you would ask the questions: where does the mail live, who sees it, whose address does the reply come from, and what does the vendor charge for the seat.

What a shared mailbox actually is#

A shared mailbox is a real mailbox with an address, but nobody signs into it directly. You give named users permission to open it from their own account, and their client shows it alongside their personal mail. When one of them replies, the reply is sent as the shared address, and a copy lands in the shared Sent folder that everyone can see. That single Sent folder is the whole point.

In Microsoft 365, Exchange Online publishes the shape plainly. You need Full Access to open and read the mailbox, and Send As (or Send on Behalf) to reply from the address. Both are permissions granted to the user, not a login for the mailbox itself. Microsoft's own documentation is clear that a mailbox created as shared does not need its own user license under the current size cap, provided you do not try to sign into it as a normal user — verify the current cap on Microsoft's shared-mailbox page before you plan capacity around it.

In Google Workspace, there is no first-class shared mailbox object the way there is in Exchange. The closest native equivalents are Gmail delegation (one Gmail user grants read-and-send access to their account to up to a set number of others) and a Google Group with Collaborative Inbox turned on. Both work; both have limits. Delegation gives you the cleanest "reply as the address" behaviour, and Collaborative Inbox gives you the assignment and resolution surface. Pick by which you value more.

Where a shared mailbox wins over the other two is stateful queue work. Support tickets, billing questions, an inbound-sales inbox: the team needs to see what has been answered, by whom, and what is still open, and they need the customer to see one address on the reply. A distribution list cannot give you the shared Sent folder because it has no store at all. A group can, but adds an extra archive layer that most small teams do not need.

What a distribution list actually is#

A distribution list is a group email address that resolves, at delivery time, to a set of member addresses. The server takes one incoming message and delivers a copy into every member's own mailbox. There is no list mailbox to open, because there is no list mailbox at all. Its purpose is one-to-many broadcast, and its behaviour matches that purpose exactly.

Microsoft still calls this a distribution group in Exchange. Google calls it a Google Group used as an email list — the default group behaviour when Collaborative Inbox is off. In both platforms the semantics are the same: a member's reply comes from that member's own address, not from the list. If you reply-all, the whole list sees your answer, and every member has their own copy in their own Sent folder. There is no canonical record of what the list did.

That statelessness is a feature. For announce@ or all-staff@, the sender wants the message to land in every inbox, and there is nothing to track afterwards. For a paging alias like on-call@ or exec-team@, the whole point is that the mail reaches personal inboxes and gets answered from personal accounts. Trying to bolt a shared history onto a distribution list is fighting the mechanism.

The mistake to avoid: using a distribution list where you need a queue. Route support@ to a five-person distribution list and, after week one, no member can tell which mails have been handled without asking the other four. There is no shared state to check, because the mechanism was never designed to hold one.

What a group actually is#

A group in the modern sense is a hybrid mechanism, and it is the one that most confuses people because both major vendors have shipped several things under the same word.

In Microsoft 365, a Microsoft 365 Group is a container that gives a team a shared mailbox, a shared calendar, a SharePoint site, a Planner board, and a Teams team, all bound to one identity. Mail sent to the group address lands in the group's own conversation view; members can choose whether copies also land in their personal Outlook inbox. It sits in a different place from a classic distribution group, which is fan-out only, and from an Exchange shared mailbox, which is one store with no calendar or files attached.

In Google Workspace, a Google Group can behave as a plain distribution list, as an announcement-only broadcast, as an email-list forum with a web archive, or as a Collaborative Inbox with assignment, resolution and labels. That last mode — Collaborative Inbox — is the one that gives a Google-side team the closest thing to a shared support queue, with the ability to assign a conversation to one member, mark it complete or duplicate, and filter by assignment status. Google's own Groups admin docs walk through turning the mode on.

Where a group wins is a mixed workload: an internal team address that receives external mail, needs a searchable archive that outlives any one member's account, and where it also helps for the mail to arrive in personal inboxes so people notice it. Product@, ops@, and cross-team project addresses are natural fits. The trade is complexity — a group carries more surface area than either of the other two, and admins need to know which mode a given group is in before they change its settings.

The three routes, drawn#

One incoming message, three different mechanisms, three different physical paths it takes after the server accepts it. The image below is the same message routed as a shared mailbox, as a distribution list, and as a group — that is the whole architectural difference in one picture.

Licensing and packaging, without numbers#

Prices and thresholds change frequently enough that any number printed here would be wrong by the time you read it. What is stable is the shape of the packaging, which is what actually drives the decision.

In Microsoft 365, a shared mailbox does not require its own user license up to a documented size cap, provided no one signs in as the shared account. Beyond that cap, the mailbox needs a full Exchange Online licence attached. A distribution group is a free directory object; it costs nothing per name on the list, though every named recipient still needs a licence to have a mailbox to receive into. A Microsoft 365 Group is the same — the group itself is a directory object, and the licence is on the members. Verify the current size cap on Microsoft's shared-mailbox page before you plan capacity around it.

In Google Workspace, Google Groups are included with the Workspace subscription; there is no per-group fee. Collaborative Inbox is a mode on a group, not a paid add-on, but it is available only on Workspace editions that expose group management to admins. Gmail delegation is included in all Workspace editions but caps the number of delegates per account. Verify both against Google Workspace Admin Help before assuming a specific tier is enough.

Third-party shared-inbox platforms — Front, Hiver, Missive — sit above the mail infrastructure and add collaboration surface. They are typically packaged as per-seat subscriptions with trials, and the pricing pages on each vendor's own site are the only source that will be right on the day you buy. This post does not print their numbers by policy, and neither should any page that wants to still be right next quarter.

Who each is genuinely for#

The temptation is to pick the mechanism that sounds most "advanced." It is worth resisting; the right pick is the one whose native behaviour matches how the address is actually used.

A shared mailbox is genuinely for teams that answer a queue as the address: two to twenty people handling support@, orders@, billing@, careers@, or a small partnerships@ inbox. The reader benefit is that the customer sees one voice, and the team benefit is one shared Sent folder that answers "did we reply?" without a standup. If your team is one person, a shared mailbox is overkill and Gmail delegation or a straight forwarding alias is enough.

A distribution list is genuinely for one-to-many broadcast where replies should come from the individual, not the list: announce@, all-staff@, board@, an on-call@ paging alias, an investors-of-fund-x newsletter, a segmented marketing list. If you find yourself wanting to see "the list's replies" as a coherent history, you have picked the wrong mechanism — the list has no history to give you.

A group is genuinely for internal teams that both receive external mail and want a searchable archive that outlives any one member: product@, engineering-oncall@, a cross-functional project@ address. On the Google side, if the team is running a support-style queue and wants assignment and resolution built in, Collaborative Inbox is the shape to reach for. On the Microsoft side, Microsoft 365 Groups are the natural pick when you also want the calendar, files, and Teams surface, not just the mailbox.

There is a fourth reader we should scope out honestly: if you are running a busy customer-support queue with SLAs, formal assignments, internal comments per message, and CSAT surveys, none of these three mechanisms by themselves will feel like enough. That is what purpose-built shared-inbox platforms are for, and it is where they earn their subscription.

A third option, honestly: the client layer#

None of these three is a client. A shared mailbox, a distribution list, and a group all describe what the mail server does with a message — they say nothing about the software the team uses to actually read and answer it. You still need something to open the mailbox from.

That is where we sit, and this is where the disclosure belongs: [we build AI Emaily](/). It is an AI-native email client that connects to a Microsoft 365 mailbox, a Google Workspace account, or standard IMAP, so a team that has already picked a shared mailbox can use AI Emaily as the reading and drafting UI on top of it. It does not replace the mailbox mechanism, and it should not be sold as one. If you route support@ to a distribution list, AI Emaily cannot conjure a shared history that never existed — the mechanism decision has to be right first.

Where AI Emaily concedes ground: purpose-built shared-inbox platforms like Front, Hiver, and Missive ship a collaboration surface — formal assignment queues, per-message internal comments, CSAT and QA — that a general email client working against a raw shared mailbox does not. If your team needs those in the inbox, buy one of those platforms. If your team is fine reading and drafting in a real mail client and wants an AI layer for triage, categorisation and reply-drafting, that is what AI Emaily does. If cost is the deciding question, [AI Emaily pricing](/pricing) is a 7-day free trial on Pro or Autopilot rather than a free tier.

Common failure modes#

A short list of the mistakes that keep repeating, so you can catch them before they compound.

• Using a distribution list where you need a queue. Nobody can tell what has been answered, because there is no shared state. Fix: promote to a shared mailbox or a group.
• Using a shared mailbox as a broadcast list. Every member has to open the mailbox to see the announcement. Fix: use a distribution list — that is exactly what it exists for.
• Assuming a Google Group is a shared inbox. A plain Google Group is a distribution list. Only a Google Group with Collaborative Inbox turned on is a shared queue with assignment and resolution.
• Signing into the shared mailbox as a user. It works, and it is exactly what Microsoft's own docs tell you not to do. Grant Full Access and Send As instead, then block sign-in for the shared account.
• Building the on-call rota with a shared mailbox. Copies do not land in personal inboxes, so people miss pages. Use a distribution list, and let each on-call member's own client alert them.
• Forgetting that a group has modes. A Google Group flipped between announcement-only, email-list, and Collaborative Inbox behaves very differently in each mode. Confirm the mode before you troubleshoot behaviour.

How to decide, in one pass#

Read the questions in order. The first one that gets a clear yes tells you the mechanism.

1. 1

   Does the team need to see who has already answered a customer, on the same address?

   If yes: shared mailbox. This is the only one of the three with a single Sent folder for the address. Stop reading and go create one.

2. 2

   Is the address purely one-to-many, with replies expected to come from the individual?

   If yes: distribution list. No shared store means no state to maintain and no confusion about whose reply is authoritative. Members' inboxes are the record.

3. 3

   Do you need both a searchable group archive and delivery to some members' personal mailboxes?

   If yes: group. Microsoft 365 Group on the Microsoft side; Google Group with Collaborative Inbox on the Google side if assignment and resolution matter, plain Google Group otherwise.

4. 4

   Do you also need formal assignment queues, internal per-message comments, and CSAT built in?

   If yes, buy a shared-inbox platform like Front, Hiver, or Missive on top of the mechanism above. The three native mechanisms are not designed for that workflow.

5. 5

   Do you want an AI-drafted, AI-triaged reading UI on top of your shared mailbox?

   That is what we build. Disclosure: we build AI Emaily. It connects to Microsoft 365, Google Workspace, or IMAP, and works the mailbox — it does not replace the mechanism decision above.