Mail-tester vs Folderly
Side-by-side from the Top 11 ranking of The 11 Best Email Deliverability Tools. Last verified June 15, 2026.
The short answer
Mail-tester ranks higher on Top 11 (#3 vs #5) for Email marketers and developers improving inbox placement rates. The fastest, simplest tool for a single pre-send spam check and technical audit.
At a glance
| Mail-tester | Folderly | |
|---|---|---|
| Top 11 rank | #3 / The 11 Best Email Deliverability Tools | #5 / The 11 Best Email Deliverability Tools |
| Score (out of 9.4) | 8.8 | 8.3 |
| Best for | Quick, on-demand spam checks | Fixing cold outreach deliverability |
| Pricing | $ (Pay-as-you-go or $50/mo) | $$$ ($200 to $2000/mo) |
| HQ | London, UK | Wilmington, USA |
| Founded | 2014 | 2019 |
Mail-tester
The fastest, simplest tool for a single pre-send spam check and technical audit.
www.mail-tester.com/Folderly
A specialized platform for fixing deliverability problems common in cold email campaigns.
folderly.com/Methodology and scoring weights live at /methodology. No vendor pays for placement — see about.