We are excited to announce the general availability of the Inbox OSS Email Validation engine. Seven distinct checks — syntax, DNS, SMTP probe, catch-all, risk databases, MX blacklist, and WHOIS domain age — combine into a single verdict per address.
The pricing: 100 free per month on every plan, with paid tiers starting at $0.0005/check. Bulk uploads supported. Pre-send validation hooks let you validate inline right before /mail/send.
We benchmarked against five major validation services. We match or beat all of them on bounce-rate prediction. The WHOIS check in particular catches a class of disposable addresses no one else flags.
Try it free at the API or via the bulk uploader in your dashboard.