Mailwarm

Mailwarm, a Y Combinator-backed company trusted by more than 10,000 teams including Michelin and Microsoft, is an email warmup tool that improves sender reputation and email deliverability to keep campaigns out of spam folders. It sends automated warm-up emails to more than 50,000 real inboxes daily, provides real-time inbox-versus-spam placement tracking with 24/7 monitoring, and supports Gmail, Outlook, Yahoo, Zoho, AWS, SendGrid, Mailgun, and other SMTP platforms. Every plan includes deliverability expert consultation and a dashboard to monitor and control warming intensity. Mailwarm does not offer a traditional free trial, but email warmup begins immediately after linking an account, with the ability to change plans later and cancel anytime.