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Keep Instantly for sending. Upgrade the inbox.

Instantly calls its built-in reply tool the “Unibox.” It shows replies from Instantly campaigns in that account. Master Inbox reads every mailbox you own, across every sequencer, every client workspace, and LinkedIn.

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Free 7-day POC. Unlimited users on every plan.

The real Master Inbox: replies from every mailbox labeled by intent, with campaign attribution

Instantly is a strong sequencer and this page is not about sending. If you run one account and never touch LinkedIn or inbound leads, the Unibox may cover you fine. The comparison below is about what happens once your team runs more than that.

What is the Instantly Unibox?

The Instantly Unibox is the reply view built into Instantly. It collects replies to campaigns sent from that Instantly account into one feed. It works well for what it covers. It does not show replies from other tools or accounts, LinkedIn conversations, inbound leads, or mailboxes connected outside of Instantly.

Master Inbox vs the Instantly Unibox

Both promise one inbox for your replies. Instantly's Unibox is scoped to campaigns sent from that Instantly account. Master Inbox is a reply layer that sits on top of every account, every workspace, and every sending tool you run.

	Master Inbox	Instantly
Built for	Every mailbox, every tool, every client workspace	Replies inside one Instantly account
Scope of replies	All connected mailboxes across every sequencer and workspace	Only campaigns sent from that account
Forwarded / CC'd / address-change replies	Caught directly via mailbox connection; roughly 12% more replies captured in our internal data	Missed if the reply doesn't route back through Instantly's send
LinkedIn replies	Same thread as the email conversation, per prospect	Not tracked
Inbound form leads	Routed into the same inbox, tagged and assigned	Not supported
Multi-tool agencies	One inbox spans Smartlead, Instantly, EmailBison, HeyReach, Lemlist and more	Sees only Instantly sends
AI on replies	Intent labels, drafts in your voice, reply agents that can answer and book	Rules-based assignment and tags; no outbound intent labels or reply agents
SLA / response-time reporting	Built in, per client and per rep	Not available
Users	Unlimited on every plan	Priced per seat
Campaign attribution across tools	Every reply linked to the sequencer, campaign and lead that produced it	Instantly campaigns only

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Comparison last verified: August 2026. Competitor features and pricing change; tell us if a row is out of date.

Why agencies add Master Inbox on top of Instantly

None of this is about Instantly's sending. It is about what happens to a reply once it leaves the Unibox's view.

Replies from every client workspace in one Master Inbox view

One account is not the whole agency

Agencies run separate Instantly accounts per client. The Unibox shows one account's campaigns at a time, so a manager checking client health opens accounts one by one. Master Inbox merges every client workspace into a single view with role-based access.

AI intent labels on replies in Master Inbox

Forwarded replies get missed

A prospect forwards a reply, CCs a colleague, or replies from a changed address, and a campaign-bound Unibox can lose the thread. Master Inbox connects mailboxes directly rather than relying on the send path; in our internal side-by-side data, direct connections catch roughly 12% more replies.

Reporting in Master Inbox: SLAs, reply coverage and channel breakdowns

LinkedIn never shows up

Instantly sends email. Half of an SDR's real conversations happen in LinkedIn DMs after the email lands. Master Inbox threads LinkedIn and email together per prospect, so the reply that matters is not sitting in a different app.

Inbound leads have nowhere to go

A form fill or an inbound reply that never touched an Instantly campaign has no home in the Unibox. Master Inbox routes inbound leads into the same queue your team already works, tagged and assigned like any other reply.

No SLA reporting across the team

The Unibox tells you what came in. It does not tell you how fast your team answered it, or which client's replies are aging. Master Inbox reports response time and SLA per rep and per client.

Seats add up fast

Adding a QA reviewer or a client-side approver to the Unibox means another paid seat. Master Inbox includes unlimited users on every plan, so the team around the inbox can grow without a bigger bill.

Questions we get

Is there a better Instantly unibox alternative?

Yes. The built-in Unibox only shows replies from campaigns sent through that Instantly account. Master Inbox reads every connected mailbox across every account, every sequencer, and LinkedIn, with AI labeling, reply agents, and SLA reporting the Unibox does not have.

Can I keep sending with Instantly?

Yes. Master Inbox does not touch sending. Instantly keeps running your campaigns exactly as it does today; Master Inbox connects natively and catches every reply those campaigns generate, plus everything else that lands in your mailboxes.

What does the Instantly Unibox miss?

Replies from other tools and other accounts, LinkedIn conversations, inbound form leads, and anything that arrives by forwarding or from a changed address. It is scoped to that one account's own Instantly campaigns.

Does Master Inbox replace Instantly?

No. Instantly sends your campaigns. Master Inbox is what happens after send: it captures, labels, and routes every reply, across every tool, into one inbox your whole team works from.

Do I need Master Inbox if I only run one Instantly account?

Yes, if you care about missed replies and speed to lead. Unibox only sees replies to Instantly campaigns, so the forward, the CC and the new-address reply never show up, however small the account. Master Inbox catches those, puts an SLA on the interested ones, and gives your clients a cleaner view than a sequencer tab if they look at the inbox too. Add LinkedIn, a second client or a second sending tool and the case only gets stronger. Make the switch; Instantly keeps sending.

How does Master Inbox connect to Instantly?

Natively, by API key. Every Instantly campaign and reply syncs in, and activity flows back to Instantly and your CRM, so nothing needs to be copied between tools by hand.

Is there a free trial?

Yes, a free 7-day proof of concept connected to your real Instantly accounts and mailboxes, not a demo environment.

Do agencies running multiple Instantly accounts need anything special?

No special setup. Each Instantly account connects to Master Inbox as its own client workspace, with isolated views and optional white-label access for the client, all inside one login for your team.

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