Warmbox

Warmbox automates email warmup using AI to pick strategies that match your sending pattern, and its 35,000+ domain network simulates real engagement with your emails. It targets time zones so warmup emails land when recipients typically open mail, making the activity look more natural than batch sends.

It's built for teams that want warmup done intelligently rather than with generic templates. If you're launching new domains or want to protect an aging sender IP, Warmbox handles the technical setup without requiring you to think about the details of what "real" warmup engagement looks like.