Lyris’s Content Checker
This SpamAssassin powered tool will determine your spam compliance in the form of a user-friendly spam score. You will also get advice on how to improve this score and make sure that less of your campaign ends up in the spam folder.
Email Spam Test
Another powerful tool provided by SpamAssassin, it will give you a slightly different perspective and additional protection against spam filters and spam traps.
Contactology’s Email Spam Checker
An extremely useful spam checker that will help you rate message quality and deliverability on a scale of 0-100. It’s recommended to use multiple spam checkers in order to get the best insight possible.
Return Path’s Sender Score
Sender Score data is a great way to make the e-mail system more efficient and enjoyable to everyone. You just enter your sender domain name or IP and you will get detailed metrics and advice on how to improve it. This way you can quickly learn to avoid spam filters.
Send Forensics’ Email Deliverability Test
A unique and free tool for deliverability testing, which you should use on every campaign. You will be provided with detailed data and comparisons to other senders in your niche.
MXToolBox This powerful tool is more suited to advanced users, but it will also give you some interesting insights into the campaigns you are sending.
Validatemy.email
Best mailing list validation tool on the market, multi-step email validation through custom tailored solution.