MxToolbox is a website that offers a suite of free tools that can help you check and diagnose any email or website related problems. With its easy-to-use interface, users can input a domain name or IP address to instantly retrieve information such as DNS lookup, blacklist check, email diagnostics, and more. In addition to its free services, MxToolbox offers paid packages that provide more comprehensive monitoring and management of email servers and domains. The website is an invaluable resource for IT professionals, web developers, and anyone else who needs to troubleshoot and optimize email and web performance.