The Spam detection tab scores each captured email against a set of common spam-filter rules and shows you exactly which ones it triggered. Fixing these before you send improves the odds your real email lands in the inbox instead of the spam folder.

Each triggered rule explains what it found and why it matters, so the score is actionable rather than just a number.

MailSandbox inspects the message for the patterns spam filters weigh most heavily, including:

• Remote images — a high image-to-content ratio or images loaded from many external hosts
• Missing text part — HTML-only messages with no plain-text alternative
• Suspicious links — mismatched link text and targets, or risky URLs
• Excessive capitalisation — shouting subject lines and body copy in ALL CAPS

Pair this with the HTML compatibility check and blacklist check for a complete deliverability picture before you send for real.