5 Email Warmup and Deliverability Improvement Tools for Agencies

An email warmup tool is a software that gradually increases the sending volume of a new or inactive email account. It simulates natural engagement (opens, clicks, replies) to build sender reputation and improve inbox placement.

Agencies often send large volumes of cold emails. Without warming up, emails are likely to land in spam. Warmup tools protect domain reputation, improve deliverability, and help maximize response rates for client campaigns.

The warmup period typically lasts 2–6 weeks depending on the tool, sending domain reputation, and volume goals. Some tools offer smart-ramp systems that automatically adjust sending frequency.

Yes. Most tools like Instantly and TrulyInbox allow unlimited email accounts to be connected and warmed simultaneously, making them ideal for agencies managing multiple clients.

Yes, when using reputable services. Tools like Warmy.io and Allegrow use real inbox networks and comply with authentication standards (SPF, DKIM, DMARC), ensuring safe and effective warmup.

Some platforms, like Folderly and Instantly, provide AI-powered copy suggestions and spam trigger detection, helping agencies craft messages that avoid spam filters.

No. Warmup is an ongoing process. Even after initial warmup, continued activity helps maintain sender reputation, especially for agencies with high-volume campaigns.

While all five tools have unique strengths, Instantly is often preferred by agencies for its massive warmup network, one-click activation, and scalability.