WarmInbox — Email Warmup vs mailX by mailwarm (YC S20)
Side-by-side comparison of features, pros & cons, pricing, and community votes (2026).
🏆 WarmInbox — Email Warmup leads with 0 upvotes

Email warmup: 3 mailboxes for what others charge for one
WarmInbox — Email Warmup is an innovative SaaS tool designed to help email marketers, sales teams, and outreach professionals improve their deliverability and inbox placement. Unlike traditional warmup solutions that charge per mailbox, WarmInbox offers a cost-effective approach by providing multiple mailboxes on its plans—3 on the Starter plan and up to 10 on Pro—making it an attractive choice for teams managing multiple campaigns. The platform connects via SMTP/IMAP and simulates human-like email activity by sending realistic emails daily between a pool of real accounts, marking them as read, and replying at a 40% rate. Over four weeks, users can observe their warmup score rise from 0 to 100, indicating improved sender reputation. It works seamlessly with Gmail, Outlook, and custom domains, making it versatile for various workflows. The free plan with a single mailbox and no credit card requirement makes it accessible for newcomers to test its capabilities.
Pros
- Cost-effective with multiple mailboxes included in plans
- Realistic email activity that boosts deliverability
- Supports Gmail, Outlook, and custom domains
- Progress tracking through warmup score over 4 weeks
- Free plan available with no credit card required
Cons
- Limited details on advanced customization options
- Potentially slower warmup process compared to dedicated email deliverability tools
- No information on integrations with popular marketing platforms
Best for
- • Preparing new email accounts for outreach campaigns
- • Improving deliverability rates for cold email sequences
- • Managing multiple email campaigns across different domains
- • Rehabilitating sender reputation for dormant or low-volume accounts
Pricing: Likely a freemium model with a free plan offering one mailbox, and paid plans starting around $29/month for additional mailboxes, with higher tiers offering more mailboxes at increased prices.

Email deliverability toolkit for humans and AI agents
mailX by mailwarm is an innovative email deliverability toolkit designed for both human users and AI agents. It helps diagnose why emails are ending up in spam folders by providing clear, actionable insights and precise steps to improve sender reputation and inbox placement. Built with ease of use in mind, mailX streamlines the troubleshooting process, saving users time and reducing frustration associated with email deliverability issues. Its API and MCP readiness make it highly adaptable for integration into larger marketing workflows or AI-powered systems. Whether you're an individual email marketer or a developer building automated email solutions, mailX offers a robust, user-friendly way to enhance email deliverability and ensure your messages reach the intended audience.
Pros
- Provides clear explanations and step-by-step solutions to improve email deliverability
- Designed for both humans and AI agents, enabling seamless integration
- API and MCP ready for easy automation and customization
- Speeds up troubleshooting, saving time and reducing guesswork
- Focuses on actionable insights to improve inbox placement
Cons
- Limited user base or reviews, as indicated by no votes on ProductHunt
- Details on pricing are not specified, so cost-effectiveness is uncertain
- May require technical knowledge for full API integration
Best for
- • Diagnosing why marketing emails go to spam and fixing deliverability issues
- • Integrating email deliverability checks into automated email campaigns
- • Helping AI agents improve email sending performance
- • Providing actionable insights for email compliance and reputation management
Pricing: Likely follows a freemium or subscription-based model, with free tier options and paid plans starting around a moderate monthly fee, depending on usage and features needed.