This guide outlines the essential criteria for selecting an email security vendor. It presents a list of 27 requirements that potential vendors should meet, aimed at assisting organizations in making informed decisions. Key features highlighted include the necessity for AI-enabled solutions that utilize machine learning to combat sophisticated attacks, and the importance of deploying security measures as an API for quick and extensive installation. The document emphasizes inline security deployment, which scans emails before they reach the inbox, thereby enhancing protection against threats. It details the critical need for effective phishing management, noting that Avanan’s solution can reduce phishing threats by 99.2%. Additionally, the guide discusses the importance of malware scanning capabilities to automatically check messages and files for potential threats. To address Business Email Compromise (BEC), the document outlines the need for contextual analysis and account takeover protection, ensuring comprehensive security measures are in place.