Bearer authentication
Create revocable API keys in Workspace. Keep keys on your server and never expose them in browser code.
Transparent responses
Every verdict includes normalized input, status, reason, confidence, and individual check evidence.
Asynchronous bulk jobs
Upload CSV/TXT, poll job progress, inspect partial results, and export when completed.
Verify one address
curl https://verifier.bestsender.app/api/v1/verify \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"email":"person@example.com"}'
Verdict statuses
valid— decisive positive mailbox evidence was available.invalid— decisive syntax, domain, or mailbox rejection evidence was available.risky— the address or domain has signals such as role, disposable, typo, or catch-all behavior.unknown— available evidence cannot responsibly prove validity or invalidity.
Operational safeguards
Requests are rate limited, tenant scoped, credit controlled, and logged. SMTP checks are non-sending and may be disabled when infrastructure reputation prevents trustworthy evidence.