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Email validation: classify recipient risk before you send.

Understand WillItInbox recipient validation, including syntax, MX, SMTP probes, catch-all domains, disposable addresses, role accounts, typos, and confidence.

Open validator Validation API

validation layers

CSV

bulk uploads

API

automation ready

Validation result categories

WillItInbox avoids false certainty. It separates confirmed failures from risky or inconclusive results so you can decide how aggressive your suppression policy should be.

Status	Meaning	Typical action
valid	The mailbox appears reachable.	Keep, but still monitor bounces.
invalid	Syntax, domain, or mailbox evidence says it should not receive mail.	Suppress before sending.
risky	Catch-all, role, disposable, or policy signals raise risk.	Segment or verify with care.
unknown	The domain or mailbox probe did not provide reliable evidence.	Retry later or send conservatively.

Signals WillItInbox checks

The validator combines cheap deterministic checks with network evidence and conservative SMTP interpretation.

Syntax normalization, typo detection, disposable domains, role accounts, free-provider hints.
DNS and MX discovery before attempting mailbox-level checks.
SMTP mailbox probe, catch-all detection, and provider-aware response classification.

Where validation fits

Validation is strongest before imports, cold outbound, signup enrichment, reactivation campaigns, and list hygiene sweeps.

Before import

Reject obvious bad addresses before they enter your CRM or product database.

Before campaigns

Reduce hard bounces and risky recipients before reputation damage happens.

In product

Use the API to validate signups or high-value workflow addresses.