Mailchk is an email verification and deliverability platform that protects your business at every stage of the email lifecycle — from signup to inbox. With Mailchk, you can validate email addresses in real time at the point of entry, blocking fake, disposable, and scam addresses before they ever reach your database. Clean existing lists via bulk CSV upload, detect catch-all domains, and strip out role-based and aliased addresses that skew your metrics and hurt your sender reputation. Beyond validation, Mailchk gives you full visibility into your email pipeline. Test transactional and marketing emails end-to-end using real inboxes, inspect HTML rendering and headers, and verify inbox placement across Gmail, Outlook, and Yahoo before you hit send. Email Watchdog provides always-on monitoring so you're alerted to deliverability issues before they impact your customers. For teams who need signup protection without writing backend code, Form Guard embeds directly into your forms with a single script tag.