Email
Validation
Check an address is real and deliverable before you send. Keeps bad addresses off your list, cuts bounces, and protects your sender reputation — pay-as-you-go, no subscription.
Validate before
you send
One request, one verdict. No probe emails are ever sent to the address — validation is invisible to the recipient.
curl -X POST https://api.posthawk.dev/v1/validate \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "email": "user@example.com" }'{ "decision": "deliverable", "confidence": "HIGH", "checks": { "validSyntax": "HIGH", "validDns": "HIGH", "mailboxExists": "HIGH", "disposable": "LOW" }}Two engines,
one verdict
Native checks first
Syntax, live DNS/MX lookups, disposable-domain and role-address lists, and gibberish detection — anything obviously bad is rejected immediately.
Mailbox-level backup
Addresses that pass are confirmed at the mailbox level by our backup verifier — catching non-existent inboxes (even at Gmail) and catch-all domains.
One clear verdict
Deliverable, risky, undeliverable, or unknown — with a per-check breakdown so you know exactly why.
Real-Time API
Validate a single address in one call — at signup, at checkout, anywhere. Same API key you already use for sending.
List Cleaning
Paste or import a list and clean it in bulk. Undeliverable addresses are flagged before they ever bounce on you.
Import Validation
Tick one checkbox when importing contacts and undeliverable rows are skipped automatically — with a clear upfront cost estimate.
Sign-up Protection
Validate newsletter sign-ups before the confirmation email goes out. Fake and disposable addresses never reach your list.
Risk Flags
Role addresses (info@, admin@), disposable domains, and random-keyboard input are flagged so you can decide what to keep.
Free Re-checks
Already-validated addresses are cached — re-checking the same address costs nothing. Duplicates and suppressed addresses are free too.
Pay as you go.
Nothing up front.
Validation is an opt-in add-on for Pro and Scale plans — turn it on in your workspace settings when you need it, turn it off when you don't. No monthly fee, no credit packs that expire.
$15 per 1,000 checks — billed only for what you use, on the invoice you already have.
- Re-checking a known address is free
- Duplicates and suppressed addresses are free
- Off by default — enable it when you need it
Deliverable
Real mailbox, safe to send.
Risky
Role, disposable or catch-all — your call.
Undeliverable
Doesn't exist — remove before sending.
Unknown
Couldn't determine — treat with caution.
Stop sending to addresses that bounce
Clean your list once, validate at the edge forever. $0.015 per check, only when you use it.