Valimail Domain Checker is a tool designed to assess domain security configurations related to email authentication. Based on the product name and URL reference to "instrant-spf," the tool evaluates domain protection status by checking email authentication protocols. The tool provides domain security verification capabilities, allowing organizations to determine if their domains are properly configured to prevent email spoofing and unauthorized email sending. Users can check their domain's security posture through the domain checker interface. The tool focuses on SPF (Sender Policy Framework) configuration analysis, which is a critical component of email authentication infrastructure. SPF records help prevent email spoofing by specifying which mail servers are authorized to send email on behalf of a domain. Organizations can use this tool to identify potential vulnerabilities in their email authentication setup and ensure their domain is protected against email-based threats such as phishing and business email compromise attacks. The domain checker serves as a diagnostic tool for email security, providing visibility into domain configuration status and helping organizations maintain proper email authentication standards.