Team inbox software: choose by access model, not by feature list

Why sort by access model rather than by feature count

Every tool in this category can list features: assignment, canned replies, an AI reply-composition button. A feature list makes every option look similar, because most vendors eventually add most features. What actually differs — and what a team lives with for years — is how the tool reaches your mail, who owns any AI feature bundled into it, and how much structure it forces onto a queue before the queue needs that structure.

A tool that lives inside the Gmail interface behaves differently from one that moves your team into a separate application, which behaves differently again from a mailing list your Workspace admin already controls. Sorting by that dimension — access model — answers the questions that actually matter: what happens to a rule when nobody has the tab open, what a reviewer can reconstruct after the fact, and whose agent is touching a customer's mail.

Five category shapes

Native Google Groups Collaborative Inbox

A mode any Google group can be switched into. Google does not publish a price for the feature on the pages checked, and does not state which Workspace editions include it — the one prerequisite it does state is that Groups for Business must be turned on. Google's own documentation states that group owners and managers can make any group a Collaborative Inbox, where members with the right permissions can take a conversation they volunteer to respond to, assign responsibility to another group member, mark a conversation as complete, duplicate, or no action needed, and search for conversations by resolution status or assignee. Conversation history has to be turned on first. Source: support.google.com/a/users/answer/10375787, checked 2026-08-11.

The published numeric limits Google states for these groups — forwarding, inbound volume, message size, member additions — and Google's own upgrade path once a team reaches one, are set out in full on Google Groups Collaborative Inbox: capabilities and published limits.

Google publishes no member ceiling for a Collaborative Inbox group — total group membership is stated as unlimited — and no Collaborative-Inbox-specific size recommendation. Google's own upgrade pointer, for teams that outgrow this shape, is to set up delegated Gmail accounts instead: "For advanced collaboration, set up delegated accounts in Gmail, where you can share inboxes among 40–1,000 users." Same source, checked 2026-08-11. See shared inbox for Gmail for what a Gmail team needs once agent controls, not just Collaborative Inbox actions, come into play.

Gmail-layer tools

These live inside the Gmail interface rather than replacing it. Four vendors publish current pricing. Every price, plan name, and trial length below is that vendor's own published wording about its own product — DuoInbox publishes no price and offers no trial, so none of these figures implies anything comparable from DuoInbox.

• Hiver in Gmail — Free plan at $0, "Free forever." Growth is $25/user/month billed annually or $35 billed monthly; Pro is $55/$65; Elite is $85/$95. All plans start at 2 seats, increasing from 2 to 5 and then in increments of 5 seats. Hiver publishes a 7-day free trial. Sources: hiverhq.com/pricing/hiver-in-gmail for the plan prices and hiverhq.com/pricing for the seat increments and the trial, both checked 2026-08-11.
• Gmelius — Meli is $19/user/month billed yearly ($21 monthly); Growth is $25/user/month yearly ($33 monthly); Pro is $40/user/month yearly ($50 monthly). Enterprise is a custom quote with a stated minimum of 50 users — Gmelius's own page shows a conflicting per-seat figure elsewhere on the same plan comparison, so only "custom quote" and the 50-user minimum are stated here. A 7-day free trial is published. Source: gmelius.com/pricing, checked 2026-08-11.
• Drag — Starter is $12/user/mo billed yearly ($16 billed monthly); Plus is $18/$22; Pro is $24/$30. A 7-day free trial is published, and Drag's own pricing page carries the caveat "Prices are per user, billed annually, and may change." Source: dragapp.com/pricing, checked 2026-08-11.
• Keeping — Essentials is $19/user/month monthly or $14 annually; Advanced is $29/$24; Enterprise is $59/$49. Every plan carries a stated "2 User Minimum", and Keeping publishes "Three simple plans, each with a 14-day free trial. No credit card required." Essentials publishes "2 Shared mailboxes"; Advanced publishes "Unlimited shared mailboxes." Source: keeping.com/pricing, checked 2026-08-11.

Full helpdesk / ticketing systems

Some teams need a ticketing lifecycle — categories, routing rules, and cross-channel reporting — rather than a mailbox with more collaboration features bolted on. That is a different shape from every option on this page, and the trade-offs are covered in full on shared inbox vs ticketing system rather than repeated here.

Multi-channel collaboration suites

These move a team's work into a dedicated application that pulls in more than email, rather than staying inside the Gmail interface. Missive publishes "Email, SMS, social accounts" as its channels; Front's plan comparison treats email as one channel type, listing "Email e.g. Office 365, Gmail, Custom." Check each vendor's own product pages for the current channel list.

• Front — Starter is $25/seat/mo, up to 10 seats; Professional is $65/seat/mo, up to 50 seats; Enterprise is $105/seat/mo with no published seat cap. The page shows "Billed Annually" with "Save 24%"; no monthly price ladder is displayed, so Front's monthly rate is not published. Front publishes a 14-day free trial offering "all the features available in our Professional plan," and states that "we require an onboarding package be purchased for contracts over $25k." Source: front.com/pricing, checked 2026-08-11.
• Missive — Starter is $14/user/month billed yearly, up to 5 users; Productive is $24/user/month, up to 50 users; Business is $36/user/month, unlimited users. Missive publishes "Try Missive risk-free for 30 days. No credit card required." Channels listed are "Email, SMS, social accounts", with integrations for Gmail & Google Workspace, Outlook, IMAP, WhatsApp, Messenger, Instagram, and SMS via Twilio. Source: missiveapp.com/pricing, checked 2026-08-11.

Customer-owned agent with governed inbox access

This is the shape DuoInbox is built as, stated here as one option among the five rather than as a verdict on the others. Instead of a mailbox tool with an AI feature bundled in, DuoInbox adds a review layer around a customer-owned agent working inside the Google Workspace shared inbox a team already has. A trigger rule decides which messages the agent may pick up; one of three permission levels — summarize only, prepare a proposed reply, or send after human approval — decides how far it may act; a review queue, Slack notifications, and audit logs give a team a record; and recipient restrictions, sending limits, and an immediate kill switch bound what can go wrong. Hermes, the initial agent, gets governed mail access through MCP rather than direct Gmail credentials, scoped to the workflow that triggered it. DuoInbox's initial focus is Google Workspace shared inboxes and Hermes.

Pricing note: DuoInbox's own pricing, packaging, and availability are not yet published, and DuoInbox does not offer a trial. This section states what the shape is, not what it costs. See AI email agents: a practical governance guide for the fuller framework behind permissions, review states, and audit trails.

Stay on the native Google option if…

Built directly from what Google publishes a Collaborative Inbox does. Source: support.google.com/a/users/answer/10375787, checked 2026-08-11.

• Your team's work fits the published capability set: taking a conversation, assigning it to another group member, marking it complete, duplicate, or no action needed, and searching by resolution status or assignee.
• The group is already on Groups for Business, or a Workspace admin can turn that on, and conversation history can be enabled — both are stated prerequisites.
• Nobody on the team needs a separate application, a per-seat subscription on top of your Workspace subscription, or an AI feature bundled into the inbox tool itself.
• You have not hit a published limit that requires Google's own named upgrade path — delegated Gmail accounts, which Google positions as the step "for advanced collaboration."

Google states plainly that its published limits "can change without notice to protect Google's infrastructure," so re-check the current numbers before treating any specific figure as fixed.

Published entry prices

Who each shape suits

A team that fits entirely inside the published Collaborative Inbox capability list, and already has Groups for Business, has no reason to add a per-seat tool on top of it — the native option is the honest answer, and nothing on this page argues otherwise. A team that wants collaboration features to stay inside the Gmail interface, without moving into a separate application, is the audience the Gmail-layer vendors above are built for. A team whose queue has outgrown a status field — multiple stages, cross-channel reporting a manager actually reads — is the audience a full helpdesk is built for, covered separately. A team that already works across email, SMS, and social channels in one place is the audience the multi-channel suites are built for. A team that wants a customer-owned AI agent to work inside the Google Workspace shared inbox it already runs, under a review layer it controls rather than a vendor-bundled agent tier, is the audience DuoInbox is built for — with its own pricing not yet published.

Frequently asked questions

What does Google Groups Collaborative Inbox cost?

Google does not publish a price for the Collaborative Inbox feature on the pages checked, and does not state which Google Workspace editions include it. What Google does state is the prerequisite: Groups for Business has to be turned on, and conversation history has to be turned on to enable Collaborative Inbox features. Source: support.google.com/a/users/answer/10375787, checked 2026-08-11. Check your own Workspace subscription rather than treating it as included.

What do the Gmail-layer tools charge to start?

As published on each vendor's own pricing page, checked 2026-08-11: Hiver publishes a Free plan at $0 ("Free forever") with Growth from $25/user/month billed annually; Drag publishes Starter at $12/user/mo billed yearly ($16 billed monthly), with its own caveat that prices "may change"; Keeping publishes Essentials at $14 per user per month annually ($19 monthly) with a 2-user minimum; Gmelius publishes Meli at $19/user/month billed yearly ($21 monthly). Compare them against your own seat count rather than against a single entry figure.

Does DuoInbox replace a shared inbox tool?

No. DuoInbox is built to add governed agent access to a shared Google Workspace inbox a team already has, rather than to replace the inbox tool itself. DuoInbox's own pricing is not yet published.

Do Gmail-layer and helpdesk tools already offer human review of AI replies?

Some do. Hiver publishes AI Agents guardrails with admin review, and Front publishes Copilot review before send as part of its own AI features. Human approval of an AI-drafted reply is not unique to any one vendor named on this page.

Independence disclaimer

Google, Gmail, and Google Workspace are trademarks of Google LLC. Hiver, Gmelius, Drag, Keeping, Front, and Missive are trademarks of their respective owners. Every one of those names is used here only to describe what that vendor's own public pages state. DuoInbox is an independent product, is not affiliated with, endorsed by, or sponsored by any vendor named on this page, and this page implies no partnership with any of them.