Mail testers typically analyze your email against a set of criteria. These may include:
Spam Score: Evaluates how likely your email is to be marked as spam. Content Analysis: Checks for problematic keywords and phrases. Authentication: Validates DKIM, SPF, and DMARC records. HTML and CSS Validation: Ensures your email is correctly formatted. Blacklists: Checks if your domain or IP is on any email blacklists.