Sales & Marketing
Warmbox
AI-based email warm-up tool that keeps cold outreach out of the spam folder
Warmbox is an AI-driven inbox warm-up tool for sales and marketing teams running cold email campaigns. It automatically sends and interacts with emails from a connected inbox — opening, replying to, bookmarking, and removing them from spam — to build sender reputation over time, using a network of 35,000+ private inboxes across major providers (Gmail, Outlook, Yahoo, Amazon SES, SMTP, and more). It supports Growth, Flat, or fully custom warm-up schedules, GPT-4/hybrid human-realistic interactions, a live DNS/blacklist checker, and a dashboard for monitoring deliverability results.
- Best for
- Sales teams, agencies, and marketers running cold email outreach who need their sending domain and inbox reputation warmed up so campaigns land in the inbox instead of spam.
- Pricing
- Solo $15/mo (1 inbox, 50 emails/day); Start-up $69/mo (3 inboxes, 250 emails/day, 3 team members); Growth $139/mo (6 inboxes, 500 emails/day, 6 team members, Enterprise support); custom Team plans for larger sending volumes on request
Core features
- • Automated email warm-up (send, open, reply, bookmark, remove from spam)
- • 35,000+ private inbox network
- • Human-realistic interactions (GPT-4 & hybrid)
- • Growth, Flat, or fully custom warm-up schedules
- • Live email checker (DNS, blacklist)
- • Reporting & deliverability dashboard
- • Integrations: Gmail/GSuite, Outlook 365, Yahoo, iCloud, Zoho, Sendgrid, Sendinblue, Amazon SES, and any SMTP inbox
- • Multi-account support for agencies and teams
Use cases
- 1. Warm up a new sending domain before launching a cold email campaign
- 2. Recover an inbox that started landing in spam
- 3. Check a domain for blacklist status and DNS/SPF/DKIM issues for free
- 4. Warm up multiple team inboxes for an outbound sales agency
- 5. Monitor spam score and deliverability trends over time on a dashboard
How to use
Connect your inbox (Gmail, Outlook, Yahoo, Amazon SES, or any SMTP provider) in about 2 minutes, choose a warm-up schedule (Growth, Flat, or custom), and let Warmbox automatically send and interact with emails while you monitor deliverability on the dashboard.
Pricing plans
Solo
$15/mo
- • 1 inbox warm-up
- • 50 emails/day
- • 1 member
- • Premium support
Start-up
$69/mo
- • 3 inbox warm-up
- • 250 emails/day
- • 3 team members
- • Premium support
Growth
$139/mo
- • 6 inbox warm-up
- • 500 emails/day
- • 6 team members
- • Enterprise support
Where it holds up
- 35,000+ private inbox network across every major email provider for realistic warm-up
- Human-realistic interactions (GPT-4 & hybrid) instead of simple auto-replies
- Free live DNS and blacklist checker included to diagnose deliverability issues
- Growth, Flat, or fully custom warm-up schedules to match campaign ramp-up
Where it falls short
- No free tier — the cheapest plan only covers a single inbox
- Team member and inbox limits scale with plan price, so agencies need the Growth or custom tier
- Warm-up needs days to weeks to show deliverability results, not an instant fix
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