Most email verifiers use old data, so emails look valid but bounce because mailbox is full or disposable.
Recently tested Invalid Bounce https://invalidbounce.com which does MX checks, SMTP validation, catch-all detection, and role-based filtering in real time (not cached DB). Bounce rate dropped from 6% to under 2%. Anyone else using real-time email verification before running cold email campaigns by integrating Invalid Bounce Api key into their CRM for business promotion or lead generation?