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Unibox

The better unibox is Master Inbox

Your sequencer's unibox shows its own sending, in one workspace, email only, and misses the forwards, CC replies and new-address replies it never sent. Master Inbox reads the mailbox itself: every sequencer, every workspace, and LinkedIn in one inbox with Needs Reply views, labels and routing.

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Free 7-day POC. Unlimited users on every plan. Works with Smartlead, Instantly, EmailBison, Reply.io, Lemlist and more.

The Master Inbox unibox: replies from every mailbox labeled by intent, with campaign attribution and smart views

Every channel in, one inbox out

Every sequencer and every LinkedIn tool feeds the same inbox, labeled the moment a reply lands.

Smartlead Instantly EmailBison Reply.io Lemlist LinkedIn tools Forms
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Master Inbox
Interested Meeting Request Information Request

What is a unibox in cold email?

A unibox is a single inbox that gathers every reply your cold email and LinkedIn outreach generates, no matter which sequencer sent it or which mailbox it landed in. Smartlead and Instantly each ship a unibox scoped to their own sends. Master Inbox is a unibox that reads every sequencer and every mailbox at once.

The gap nobody measures

Which replies does a sequencer's inbox miss?

A sequencer's inbox only shows replies that land back on the exact thread it sent. It misses replies forwarded to a colleague, CC'd onto a new thread, sent from an out-of-office chain, or sent from a changed email address. Connecting mailboxes directly, the way Master Inbox does, catches all of them.

A prospect forwards you to their colleague. Someone CCs a second decision maker. An out-of-office chain hides a "talk to Maria instead". A contact leaves and the reply comes from a new address. All of those are the hottest messages you have, and all of them can miss the tool that sent the campaign.

~12%

more replies captured when mailboxes connect directly to Master Inbox, on top of what the sequencer reports. Based on our internal data across connected mailboxes.

Replies on one campaignThis week
Direct reply on the threadSame address, same subject line
Sequencer sees it
Forwarded to a colleagueNew sender, thread history quoted
Captured by us
CC on an internal threadTwo people replying at once
Captured by us
Out-of-office chainWith the name of who to contact
Captured by us
Reply from a new addressContact changed companies
Captured by us
All five merge onto one conversation, on the right prospect.

What comes in from each source

Connect by API key in minutes. Nothing changes about how you send.

Source
What lands in Master Inbox
Smartlead

Every reply from every client workspace at once, with campaign and mailbox attribution. Labels sync both ways, so statuses never drift.

Instantly

Replies from all your workspaces in one list, campaign attributed, without cycling through separate logins.

EmailBison

Replies plus lead status, kept in step with Master Inbox labels in both directions.

Reply.io

Reply threads with the sequence and step they came from attached to each conversation.

Lemlist

Email and LinkedIn steps land on the same prospect, in the same thread.

LinkedIn tools

HeyReach, Expandi, Aimfox, Salesflow and the rest: conversations from every seat, threaded next to that prospect's email.

Reply Forms

Inbound submissions with every answer mapped to lead fields, matched against your outbound history on arrival.

Mailboxes direct

Google and Microsoft by OAuth, IMAP for the rest, plus one-click imports from Zapmail, HyperTide, ScaledMail, InboxKit, MailDoso and Cheap Inboxes. This is where the missed replies come from.

Teams routinely connect hundreds of mailboxes. The largest run tens of thousands. One operator, one screen.

Filters and saved views in Master Inbox: slice every reply by label, campaign, client and channel

Real product: filters and saved views on live reply data.

Views and filters

Save the question, not the search

Filter by client, campaign, mailbox, channel, label, or owner. Save the combination as a view and it becomes a queue your team works every morning.

  • By clientOne view per client workspace for the inbox manager who runs it, with permissions so they see nothing else.
  • By campaignWatch a launch on its own: every reply from that campaign only, across all mailboxes it sent from.
  • By intentInterested and meeting requests in one view, answered first. Out-of-office and not-now filtered out until they matter.

Where the master inbox came from

Before it was a category, it was a workaround.

In 2019 the standard way to watch replies across 50 sending mailboxes was a forwarding rule on each one, all pointed at a single address. Threads broke, and every forward spent sending volume from the mailbox you were trying to protect. The first Master Inbox, shipped that year as the v1 inbox inside OutreachBin, pulled mail directly from every mailbox instead. Sequencers later added their own reply views, and Smartlead even named theirs "master inbox", but they read only the mail their campaigns sent. Reading everything in the mailbox, including the forwards, CCs, and new-address replies, is by our estimate roughly eight times the processing work. That work is the product.

Eight logins, or one

Same replies, same team, different morning.

Before
Client A / Smartlead Client B / Smartlead Client C / Instantly Client D / Instantly EmailBison HeyReach Expandi Shared Gmail

Eight logins, checked twice a day, and the forwarded reply still gets missed.

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After
Master Inbox: all clients, all channels
Interested Meeting Request Information Request

One screen, filtered to whichever slice you are working, with labels applied on arrival.

Explore more: Reply Agents, LinkedIn Inbox, every integration, what a unibox is, pricing

Questions we get

How is this different from Smartlead's inbox or Instantly's Unibox?
Sequencers miss replies. Their inboxes only see replies to the campaigns they sent, from the address they wrote to, so the forward to a colleague, the CC, the answer from a new address and the reply to your reply-to domain never show up. They are email only, with no LinkedIn. The SDR experience is clunky: one workspace at a time, basic filters, no saved views, no obligation tracking. CRM sync is thin or missing, and there is no workflow engine to route a hot reply to Slack or update HubSpot. Master Inbox reads the mailboxes themselves, so every reply lands, threaded to the prospect, across every sequencer and workspace, with LinkedIn next to it, AI labels, Needs Reply views, workflows and two-way CRM sync. Keep the sequencer for sending. If you work replies only inside it, you will keep missing them.
Which sequencers does it work with?
Smartlead, Instantly, EmailBison, Reply.io, Lemlist and more, connected by API key in minutes, plus direct connections to Gmail, Outlook, and IMAP mailboxes.
What replies does a sequencer inbox miss?
Forwarded replies, CC'd threads, out-of-office chains, and replies after an address change routinely miss a sequencer's inbox. In our internal data across connected mailboxes, direct connections catch roughly 12% more replies than the sequencer reports.
Does Master Inbox have a mobile app?
Not yet. The web app works well in a mobile browser, so you can review and reply from your phone today, but there is no native iOS or Android app yet.
How do mailboxes connect?
Sequencers connect by API key in minutes. Mailboxes connect by OAuth for Google and Microsoft, one-click imports from Zapmail, HyperTide, ScaledMail, InboxKit, MailDoso and Cheap Inboxes, or CSV.
Can clients get their own view of the unibox?
Yes. Each client lives in an isolated workspace with scoped permissions and a simplified, white-label view, so they see their replies and nothing else.
Does labeling sync back to my sequencer?
Yes, two-way. Label a reply in Master Inbox and the status updates in Smartlead or EmailBison; label it there and Master Inbox follows. No duplicate work, no mismatched statuses.
Is it priced per seat?
No. Every plan has unlimited users; pricing follows mailboxes and client workspaces, so adding reps or inbox managers costs nothing.

See it on your own inboxes

Book a demo and watch replies from every sequencer and mailbox land in one inbox.

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