Underfive

Turn Conversations
Into Meetings.

Underfive connects to your outbound tools, reads replies to your cold emails and DMs, sends human-like responses, follows up automatically, negotiates times with leads, and sends calendar invites on your behalf.

⚡ Replies in under 5 min📅 Auto-books meetings💬 Human-like replies
Featured inBusiness.Scoop
0:00 / 0:00
< 5
Minutes
REPLYING NOW
$
$
Leads
Revenue
<5
Min Response
80%
Higher Conversions
24/7
Coverage

Harvard Business Review Study

900% More Conversions

Harvard found that responding to leads within 5 minutes dramatically increases conversion rates. That's exactly why we built Underfive.

Sound familiar? There's a better way.

Lead replies sit unanswered for hours 😫
Back-and-forth scheduling wastes everyone's time 🥶
You miss the 5-minute response window ⏰
No one follows up after the first reply 😩
Interested leads never get a meeting booked 💸

Works With Tools You Already Use

Seamlessly plug into your existing outbound stack. No complicated setup, no migration hassles.

How it works
Connect
Via API key on workspace/sender level
Lead Replies
Prospect responds to your campaign
AI Responds
Underfive reads, classifies & replies
Meeting Booked
Calendar invite sent automatically
Setup takes <5 minutes
Inbound Sources
SmartLead
Instantly
Email Bison
Heyreach
GetSales
Aimfox
LinkedIn
Underfive
Underfive AI
Reads, classifies & replies
Outputs
Slack
Google Calendar
Outlook

Don't see your tool? Let us know and we'll add it.
Anirudh - Founder of Underfive

Hey there, I'm Anirudh. After running a lead generation agency and managing 1M+ outbound emails and DMs every month, I built Underfive using the same inbox workflows, reply logic, and booking systems my team relies on every day.

This system is tested and proven. I can't wait to see you scale outbound without living in your inbox.

Anirudh's signature

How Underfive Works

Get started in under 5 minutes. Connect your tools, setup your agent, and let AI handle the rest.

Connect IntegrationAPI KeysConnect Your ToolAPI Keysk-••••••••••••••••Webhook auto-configuredConnectedSupported tools
1Step 1

Connect Your Cold Outbound Tool

Enter your API key from your cold outbound tool or connect your Gmail/Outlook. Webhooks are configured automatically — no manual setup needed.

  • Enter your outbound tool API key
  • Webhooks auto-configured by Underfive
  • Or connect Gmail / Outlook directly
2Step 2

Setup Your Inbox Agent

Configure your AI agent with your knowledge base and choose your preferred mode: Auto mode for instant responses or Human Approval mode for review before sending.

  • Upload your knowledge base and FAQs
  • Choose Auto mode for instant AI responses
  • Or Human Approval mode to review before sending
Inbox Agent SettingsConfigure Your Inbox AgentResponse ModeAuto ModeResponds instantly, no approvalApproval ModeReview drafts before sendingKnowledge Basesales-playbookFAQs.docxTraining ProgressAgent ready — trained on 2 documents
Inbox — Live ConversationLeadUnderfive AIMeeting proposedTomorrow at 2:00 PM — 30 minReplied in 47sMeeting booked
3Step 3

Underfive Responds Like a Human

Underfive automatically responds to every lead in under 5 minutes with natural, human-like conversations. It books meetings when prospects show interest and follows up intelligently to keep conversations alive.

  • 🌟
    Human-like responses in under 5 minutes
  • Automatically books meetings on your calendar
  • Smart follow-ups to nurture every lead

Setup takes less than 5 minutes • No credit card required

🔥Why Underfive

Transform Your Lead Management

Our platform delivers real business results through human-like automated conversations

⏰

Save 20+ hours per week

Automate email responses and follow-ups that would otherwise take hours of manual work.

📈

Increase response rate by 80%

Engage leads within 5 minutes of their inquiry, when they're most interested.

📅

Book 2x more meetings

Convert more leads with automatic scheduling links and intelligent follow-ups.

🚀

30% higher conversion rates

Turn more leads into customers with personalized, instant responses.

Customer Success Stories

Trusted by Growing Businesses

See what our customers are saying about Underfive

Agency Owner
"We are now using Underfive full-time for our inbox management, and we wanted to thank you for being so quick and attentive to our feature requests and bug reports. You guys are really on the ball and have gotten the product to a point that it's fulfilling our original vision. A big THANK YOU for being fast, attentive, listening to our feedback, and implementing our requests. We are really happy with Underfive!"

Agency Owner

Manages 20 Client Workspaces on Underfive

Erik Paulson
"Underfive has been a game-changer for us! Thank you to the team for integrating it with Email Bison as per our request. The reply agent truly lives up to its name - under five minutes every time!"

Erik Paulson

Founder, Vendisys

Suprava Sabat
"This tool has exceeded my expectations! I use SmartLead and the quality of replies that Underfive generates, combined with the reply agent configuration, is exactly what I was looking for."

Suprava Sabat

Founder, AcquisitionX

FAQs

Frequently Asked Questions

Got questions? We've got answers

Latest from our Blog

Insights and resources to help you optimize your sales process and inbox management.
Setup complete in under 5 minutes

Ready to Reply in Under 5 Minutes?

Join forward-thinking sales teams using AI to respond faster, convert more leads, and scale their outbound effortlessly. Get started in minutes, not hours.

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Free 14-day trial
Setup in <5 min