Underfive

Outbound Replies, Handled.
Meetings, Booked.

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.

< 5 min

Response time

10x

Higher engagement

24/7

Always-on replies

Sound familiar? There's a better way.

Replies pile up while you're in meetings 😫
Good leads go cold waiting for follow-up 🥶
You miss the 5-minute response window ⏰
Manual follow-ups eat up your entire day 😩
Hot leads slip through the cracks 💸
Connect in seconds

Works With Tools You Already Use

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

Outbound Tools
SmartLead
Instantly
Email Bison
Heyreach
LinkedIn
Underfive
SlackNotifications
Google CalendarScheduling
OutlookScheduling
Outputs
🌟Can't find the tool you use? Book a demo
⚡Flexible Agent Scopes

Control How Your Inbox Agent Works

Choose the right scope for your workflow. From workspace-wide automation to sender-specific control, Underfive adapts to how you work.

Workspace Level

Super Inbox Agent

Deploy one agent across your entire workspace. Handles all inboxes automatically without trigger keywords.

Trigger Keywords

Keyword-Based

Configure specific keywords that activate your agent. Perfect for targeted automation workflows.

LinkedIn

Senders Level

Heyreach Only

Select which LinkedIn senders the agent should act as an inbox agent for. Fine-tuned control for outreach.

⚙️
<5 min
Setup Time
⚡
<5 min
Response Speed
🔗
4+
Platforms
🎯
98%+
AI Accuracy
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.

API KEYWebhookConnectedYour ToolUnderfive
1Step 1

Connect Your Cold Outbound Tool

Add your API key from Email Bison, Instantly, Smartlead, or Heyreach. Then add our webhook URL to your tool to start capturing leads in real-time.

  • Enter your outbound tool API key
  • Copy Underfive webhook URL
  • Paste webhook into your tool settings
2Step 2

Setup Your Reply 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
Reply AgentMode:AutoManualHuman-LikeResponses
Follow-UpScheduled
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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Setup in <5 min