ClearMX verifies individual emails, CSV lists, and signups through a REST API. It checks syntax, MX, disposable, role, catch-all, and mailbox signals, then returns a verdict, 0–100 score, and a plain reason. When a mailbox cannot be confirmed, ClearMX says unknown instead of guessing. Start with 100 free verifications; Product Hunt users get 500 total with code PRODUCTHUNT500. Credits never expire.