Verify proton.me addresses

How Kavik verifies Proton Mail addresses: Proton accepts at RCPT for its own users only and runs no catch-all, so answers are definitive.

Proton Mail (proton.me, protonmail.ch, pm.me) is unusually verifier-friendly once you know its rules: it accepts at RCPT only for its own users and operates no catch-all. Misreading its throttling as a verdict is the common failure.

How Kavik verifies Proton

  • Accepts and rejections map directly: Proton’s user-unknown reply is definitive for the mailbox.
  • No catch-all exists on this platform, so a valid answer here is strong evidence, and Kavik scores it accordingly.
  • Throttling and connection limits become unknown, never invalid, because Proton rate-limits probing IPs aggressively.

What the verdicts mean here

  • Valid: Proton accepted the mailbox (no catch-all caveat applies).
  • Risky: rare on this platform; reserved for conflicting evidence.
  • Invalid: Proton’s definitive user-unknown reply.
  • Unknown: throttled this time; never billed, re-check later.
curl "https://api.kavik.email/api/v1/verify?email=jane@proton.me" \
  -H "X-API-Key: eva_your_key"

See single verification for the full response shape.