Don’t get stung :-) Here are some of my favourite tools for web perf and analytics:
Uptimerobot.com - Free tier. 50 monitors. Sends a request every 5 minutes to a website.
Pingdom.com - Free tier. Gives average response times.
Builtwith.com - eg is this a wordpress site, what webserver etc..
Deadlinkchecker.com This handles redirects well
Command line tools
Apache benchmarks load testing from the command line
YSlow for testing webpages as a browser plugin
Webpagetest.org - scores on perf, compression, caching, CDN
SSL Labs I found an incomplete SSL Cert security chain using
OWASP Zed Attach Proxy (ZAP) pen testing tool for finding vulnerabilities in web apps. I’ve only briefly used this and it pointed to the same issues as SecurityHeaders.com above.