Unibox at five clients, and Unibox at twenty
Instantly's Unibox is the right inbox for one workspace sending with Instantly. Master Inbox is what agencies move to when the client count, the mailbox count and the forwarded replies outgrow it. Instantly keeps sending either way.
Free 7-day POC. Unlimited users on every plan. Instantly stays your sending tool.
What Unibox does well
Instantly built a capable inbox for its own campaigns, and for a single workspace it is a fair choice.
Every reply to an Instantly campaign, with lead status, in the tool you already have open.
Interested, meeting booked, out of office, and an AI reply option for teams that want it.
A founder or a single team running one Instantly workspace can work replies without another tool.
Agencies told us the same thing in different words: fine at four or five clients, unmanageable at twenty.
Where it strains
Five patterns from agencies and in-house teams on calls. Each is a scale problem, not a bug.
Forwards, CC replies and answers from a new address have no campaign to attach to. One team tried forwarding every mailbox into one Gmail to catch them; threads broke and the misses stayed.
Master Inbox: reads each mailbox directly and threads by prospectAt twenty clients, an agency described missing emails and labels that disappeared, with one inbox manager covering ten workspaces and worried about what was slipping.
Master Inbox: labels are yours, applied on your key, kept on the threadClients on separate Instantly accounts mean one person switching accounts to triage 50 or 60 inboxes. Assistants need something simpler than the Unibox to work in.
Master Inbox: one queue across every account, scoped views per clientAgencies that run multiple clients inside one Instantly account need labels, warm-up tags and campaign data synced without one client's replies bleeding into another's view.
Master Inbox: workspace isolation, with sync scoped per workspaceTwo agencies moved off Instantly's AI reply because clients disliked losing control and the agent could not be tuned per client. Human-in-the-loop, per label, is the ask.
Master Inbox: reply agents that draft first, go autonomous per label, on your promptWarm-up replies pollute views and trip workflows unless something strips them before labeling.
Master Inbox: exclusions hide warm-up tags before anything sees themInternal data across connected workspaces puts the replies a sequencer never reports at roughly 12% of the total. How to count yours.
Side by side
What each one sees and does. Instantly's own docs describe Unibox; the Master Inbox column is what ships today.
| Instantly Unibox | Master Inbox | |
|---|---|---|
| Replies it sees | Replies to Instantly campaigns | Every reply in every connected mailbox, including forwards, CC, new addresses and replies after the sequence ended |
| Channels | Email plus LinkedIn from HeyReach, Expandi, Aimfox and native seats, threaded per prospect | |
| Accounts and workspaces | One Instantly workspace at a time | Every Instantly account and workspace in one queue, isolated per client |
| Labels | Instantly labels | AI labels on your own key, custom taxonomy, synced to Instantly with an allow list of which labels push back |
| Views | Per workspace | Needs Reply, waiting on me, 48 hours silent, per client, per rep, saved and shared |
| AI replies | Instantly's AI reply | Reply agents per client or per campaign, human-in-the-loop first, autonomous per label, on your prompt and key |
| Automation | Webhooks out | Workflows inside: Slack card with draft, HubSpot sync, add to or remove from Instantly sequences and subsequences, reminders, forwards, webhooks |
| Booking | Via your calendar link | Agent books on Cal.com, Calendly, Chili Piper, GoHighLevel, Google Calendar or HubSpot from live availability |
| Reporting | Campaign analytics | Reply coverage, missed replies, response times per rep and per client against an SLA |
| Client access | An Instantly client login | A workspace-scoped login, forwarded positives, or a scheduled view report with no login |
Keep Instantly. Add Master Inbox.
Sending does not change. Three steps on the first call.
Connect
Instantly by API key or OAuth, plus the mailboxes themselves, in bulk from Zapmail, InboxKit or HyperTide or by CSV. One workspace per client, even if they share an Instantly account.
Label and sync
AI labeling backfills history on your own key. Label sync to Instantly uses an allow list, so a manually set state in Instantly is not overwritten unless you say so.
Automate the hand-offs
Meeting booked removes the prospect from the Instantly sequence. Interested lands in the client's Slack channel with a draft. Not interested moves to a nurture subsequence three months out.
Instantly stays the sending tool: unlimited accounts, warm-up and deliverability are its job. Reply handling is ours.
What Instantly teams told us on calls
Paraphrased from six months of demos and onboarding calls, with names left out.
- An agency at twenty clients described Unibox as reliable at four or five and unmanageable past that, with missing emails and tags that did not hold.
- An in-house team with 250 mailboxes and offshore assistants needed an interface simple enough for assistants, with obligations (who owes a reply) rather than vanity metrics.
- Two agencies replaced Instantly's AI reply because clients wanted control back and the agent could not be tuned per client.
- A team running several clients in one Instantly account needed labels and warm-up tags synced without cross-client bleed.
- One operator triaging 50 to 60 inboxes across Instantly accounts wanted phone-found and SDR-to-call hand-offs pushed to callers automatically.
- Several asked for a bidirectional label sync where they choose which labels are allowed to push back into Instantly.
Questions we get
Does Master Inbox replace Instantly?
Why do replies go missing from Unibox?
Can several clients share one Instantly account?
Do labels sync back to Instantly?
What about Instantly's own AI reply?
What does it cost next to Instantly?
See it on your own inboxes
Book a demo and we connect an Instantly workspace live, then show you the replies Unibox did not have.
Book a demo