GTmetrix - GTmetrix is a free tool that analyzes your page's speed performance. Using PageSpeed and YSlow, GTmetrix generates scores for your pages and offers actionable recommendations on how to fix them.
intoDNS - IntoDNS checks the health and configuration and provides DNS report and mail servers report.
PageSpeed Insights - PageSpeed is addon for ...
MxToolBox - All of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.
SolveDNS - SolveDNS works to check your name servers, a records, and mail servers, SOA records for errors, consistency, efficiency and speed using several DNS tests.