3Cols vs SMTP Diag Tool
A side-by-side look at 3Cols and SMTP Diag Tool. For an in-depth review of either product, follow the links below.
3Cols
Productivity
3Cols is a free and open-source browser extension for Google Chrome that allows you to view three columns on many websites. It helps increase productivity when researching, reading articles, checking emails, online shopping, and more.
organizationproductivitybrowser-extension
SMTP Diag Tool
Network & Admin
SMTP Diag Tool is a free, open-source Windows application used to diagnose issues with sending and receiving emails. It can test SMTP servers, validate email addresses, verify DNS records, and check for common email delivery problems.
smtpemaildiagnostictroubleshooting
Related Comparisons
MxToolBox
massCode
Cacher
Upzilla
Lepton
Silent Down