Maileroo

Maileroo monitors whether your sending IPs and domains appear on major RBLs and DNSBLs, sending email alerts the moment a listing is detected. The service covers the major blacklist operators and runs checks automatically, so you don't need to remember to manually verify your reputation. Setup takes minutes and costs nothing.

Best for small senders and teams without a dedicated email ops person. It fills the gap between no monitoring and the complexity of paid reputation platforms. Works alongside your ESP as a lightweight early-warning system to catch reputation problems before they disrupt email delivery.