Everything a reply needs, in one Unified Inbox.
Underfive collects every reply from your outbound tools, puts inbox agents on each one, books the meeting, follows up, and keeps humans in control. Here is all of it.
Every reply, from every tool and client, in one view.
Stop opening five sequencers to find out who answered. Email and LinkedIn replies from every campaign land in one inbox, already classified.
Unified Inbox All clients -
Meeting bookedJordan Meyervia Email Bison -
Replied · autoEmily Tranvia Smartlead -
Follow-up · Apr 2Omar Haddadvia HeyReach -
Needs approvalLena Schulzvia Instantly
Every sending tool
PlusVibe, Email Bison, Smartlead, Instantly, Lemlist, Gmail, HeyReach, Expandi, Aimfox and GetSales in one stream.
Email and LinkedIn together
Switch between All, Email and LinkedIn without leaving the inbox.
Every client in one place
A company view across all workspaces, or drill into a single client.
Status at a glance
Meeting booked, replied, follow-up scheduled, or waiting for approval.
Thread and analysis
Read the full conversation next to how the agent classified it and why.
Filter, search, export
Filter by category or status, search by subject or address, export to CSV.
Agents that reply like your best rep, in under 5 minutes.
Each agent is trained on your offer and your rules. It reads the whole thread, works out what the prospect wants, and answers from the same sender.
Sent from the same mailbox · 2 min after the replyA knowledge base per agent
Offer, value propositions, pricing guidance, FAQs and case studies.
Auto-generate from your site
Paste your website and get a first draft of the company description.
Understanding plus drafting
One agent classifies the reply, a second writes the response in your voice.
Sentiment built in
Every reply is scored so hot leads surface first.
Objections and questions
Handled from your playbook, not from a template.
Lead website context
With Firecrawl connected, the agent reads the prospect's site before it replies.
CC and BCC by category
Loop in a closer on Interested replies, or a client on everything.
Any language, any time zone
Replies in the prospect's language and proposes times in their zone.
The meeting lands on your calendar. You never touched the thread.
When a prospect is interested, the agent proposes real times, negotiates, and sends the invite. Invites cost zero credits.
Real availability
Times come from your connected Google Calendar or Outlook.
Negotiates like a person
Handles "next week instead?" and reschedules without a human.
Invites sent for you
The calendar invite goes out and the thread is marked Meeting Scheduled.
Round-robin
Spread meetings across several calendars on the team.
No double bookings
Detects meetings that are already booked and avoids duplicates.
Your booking link too
Prefer Calendly or Cal.com? The agent can share your link instead.
Quiet threads get picked back up.
Most meetings are lost after the first reply, not before it. Agents follow up in context when a conversation stalls.
- MonAgent replied with pricing
- 3 days quiet
- ThuFollow-up 1 of 2 sent
- FriProspect replied · follow-ups stopped
One to five follow-ups
Choose how many attempts each agent makes before it stops.
Written in context
Each follow-up references the actual thread. No canned bumps.
Respects "not right now"
When a prospect gives a timeframe, the follow-up waits for it.
Stops on its own
A reply or a "not interested" ends the sequence immediately.
Humans where you want them. Nowhere else.
Decide which kinds of reply go out on their own and which wait for a person. Clear the queue wherever you already work.
Per-category control
Drag each reply category into Auto-send or Require Approval.
Approve from Slack
Drafts arrive in your channel with Approve and Edit buttons.
Nothing sent blind
Replies the agent cannot classify go to review by default.
Manual review mode
Start with every reply on approval and loosen it as trust builds.
Slack or email alerts
Get notified the moment something needs you.
From your AI tools
Review and approve drafts through the MCP connector.
Built to run many clients without many seats.
Every plan includes unlimited team members and inbox agents, and the Agency plan includes unlimited workspaces. You pay for replies handled, not for people or clients.
A workspace per client
Separate agents, knowledge, calendars and Slack channels.
Unlimited seats and agents
Team members and inbox agents on every plan. Unlimited workspaces on Agency.
Agent modes
Scope an agent to a workspace, to trigger keywords, or to LinkedIn senders.
Workspace Agent
Handle every positive reply in a client workspace with one switch.
Bring your own keys
The Agency plan lets you bring your own model keys. Replies on your keys still use credits, at a lower rate.
Managed service
Prefer we run it? Our team can handle every reply on your behalf.
Plugs into the stack you already run
Replies come in from your sending tools. Meetings, alerts and pipeline updates go out to the rest.
PlusVibe 
Email Bison 
Smartlead 
Instantly 
Lemlist 
Gmail 
HeyReach 
Expandi 
Aimfox 
GetSales.io Google Calendar 
Outlook 
Slack 
GoHighLevel 
HubSpot 🔥 Firecrawl Don't see your tool? Tell us what you send with.
Build on it, or build with it.
Run your inbox from the AI tools you already use, or wire Underfive into your own product.
MCP connector
Configure agents, review drafts and pull analytics from Claude, Cursor or Codex. One URL, no API keys.
REST API
Workspaces, agents, threads, replies and leads over a documented API.
Unlimited webhooks
Push reply and meeting events into your own systems as they happen.
The whole platform, on every plan.
The Unified Inbox, inbox agents, booking, follow-ups, approvals and integrations come with every plan. You pay for replies handled. Start with 50 free, no credit card.