For sales teams
Land in the inbox, not in spam
Free warmup builds your sender reputation before you send a single cold email. Health monitoring catches problems before they tank your deliverability.
Cold email deliverability is broken
50% of cold emails never reach the inbox. Gmail and Outlook are getting stricter every quarter. Here's what kills your deliverability:
New domains go to spam
90% of emails from new domains land in spam for the first 2–4 weeks without warmup.
Shared IPs get poisoned
1 bad sender on a shared IP can tank deliverability for everyone else on that IP.
Health degrades silently
Days before you notice your bounce rate spiked and Gmail started throttling you.
What zend.sh does for your team
Free warmup, forever
Connect your Google or Outlook inbox. Warmup starts automatically — 28-day ramp with AI content, spam rescue, and engagement simulation. No credit card, no time limit.
Health monitoring
Per-mailbox health scores updated continuously. Bounce rate, complaint rate, blacklist status, DNS health. Know exactly which inbox needs attention.
Auto-pause protection
When bounce rate exceeds 2% or complaints hit 0.3%, zend.sh automatically pauses cold sending and increases warmup. Your reputation recovers without manual intervention.
Smart mailbox rotation
4 rotation strategies distribute sends across your mailboxes intelligently. Health-weighted rotation automatically sends more from your healthiest inboxes.
Reply detection with AI
IMAP-based reply detection with AI intent classification. Interested, meeting booked, not interested, out of office — categorized automatically.
Blacklist alerts
Daily checks against 50+ blacklists. If your domain or IP gets listed, you know immediately — before your bounce rate spikes.
Works with your existing stack
zend.sh handles the infrastructure. Keep using your favorite tools for everything else.
CRM
HubSpot, Salesforce, Attio, Close — webhook events sync replies and lead status in real time.
Lead sources
Apollo, Clay, waterfall.sh — import leads via CSV or API. Custom fields for personalization.
Workflow tools
Zapier, n8n, Make — trigger campaigns from form fills, CRM events, or schedules.
Communication
Slack, email — get notified on replies, bounces, and health alerts instantly.
Ready to build on infrastructure that scales?
Free warmup, 80+ API endpoints, full SDKs and CLI. Start sending in minutes.