What tools can help with cold email warmup?

Warmup tools automate the process of building sender reputation through simulated engagement. They work by connecting your sending account to a network of other accounts that exchange and interact with messages.

How they operate: Your account sends emails to other accounts in the pool. Those accounts open, reply, and mark messages as not spam. Your account does the same for others. This creates positive engagement signals that mailbox providers observe.

Common platforms: Lemwarm, Warmup Inbox, Instantly's built-in warmup, Mailwarm, and similar services. Many cold email platforms include warmup features.

Limitations to understand:

Artificial engagement isn't real engagement

Mailbox providers may detect warmup patterns

Pool quality varies significantly by provider

Warmup doesn't fix bad sending practices

Best use: Warmup tools work best as a supplement to real engagement, not a replacement. Use them during initial ramp-up, but don't rely on them indefinitely. They help you leave port, but they won't steer the ship.