Warmbox

I wouldn't recommend Warmbox in case you really don't wanna end up in spam folder. I was using this tool for two month and it was saying everything is fine, 0% spam. However the first email I sent to myself landed in spam folder. Then I checked my email with another tool and 57% out of all emails landed in spam! Therefore I was having useless email-campaign for a month prior that. Warm-up didn't work at all, maybe made it worse. Also it exchanges emails exclusively with gmail-accounts, no yahoo or corporate emails. Support usually replies on the next day. I got refund for the second month, so thanks for that at least.

Warmbox helped us to reach out to more prospects, and to fix our spam issues (more than 50% of our emails didn't make it to the inbox before using the tool). The setup is easy (we use Gmail) and the support team assisted us during all the process. After one month of warm-up and a few edits on our SPF and DKIM, we finally got results higher than expected!

Despite the fact they claim they use all major email service providers to warm up your mailbox, they use ONLY GMAIL!!!! When I noticed that, I requested all the statistics (about ESP used) for the last few months - no one has sent me the info since the request.... Besides that, even the gmail had zero improvements, so there was no value at all.