IPQS Email Validator

Email verification service that checks syntax, domain, mailbox existence, and disposable-provider status. Has a limited free tier.

Free SMTP-level check of whether a mailbox exists, without sending an email.

One identifier in, one reconciled view out: runs an email, username, phone or domain across the OSINT APIs you hold keys for (OSI, Dehashed, Opsis) and merges results with per-source attribution.

Recovers partial phone digits from the password-reset pages of services and builds candidate full numbers.

Reputation API for email addresses that reports age, breach exposure, social profiles, disposable/free provider status, and suspicious activity flags.

Web lookup for an email or phone that shows the linked Google account (name, photo, Maps reviews) and registrations on dozens of services.