About Mailsim

Mailsim is an email simulation and warming platform built for teams and individuals who depend on email deliverability. Whether you are running cold outreach, sending transactional emails, or launching marketing campaigns, landing in the inbox is everything.

We built Mailsim because we were frustrated with the existing options. Most email warming tools charge a premium for basic features, lock deliverability testing behind expensive tiers, and require sales calls just to get started. We wanted something different — a self-service platform where every plan includes every feature, setup takes minutes, and pricing is straightforward.

What we do

Mailsim automates the process of building sender reputation. When you connect an email account, our system sends and receives emails between your address and our warming pool. Pool accounts open, read, star, and reply to your messages — generating the positive engagement signals that email providers like Gmail and Outlook use to decide whether your emails deserve the inbox or the spam folder.

Beyond warming, Mailsim gives you the tools to test your actual email templates against enterprise-grade security filters, check your domain against DNS blacklists, and analyze full email authentication headers — all included in every plan.