Email Verifier API · Rate Limits

Email Verifier Api Rate Limits

Email Verifier API does not publish numeric per-second / per-minute rate limits in its v2 documentation. Throttling is enforced through the credit balance: every "Paid" verification event consumes one credit, and the response returns the remaining balance in the `remaining` field. The free web tool exposes a separate per-user daily allowance of 5 verifications. Customers running high-volume traffic should coordinate with the vendor through [email protected] to confirm any platform-side throughput ceilings.

3 Limits Throttle: 429
Email VerificationDeliverabilitySMTP CheckRate Limiting

Limits

Credit balance (paid events) api-key
credit
customer balance
Each Paid event (mailboxExists, mailboxDoesNotExist, mailboxIsFull) consumes one credit. Free events (invalidSyntax, domainDoesNotExist, mxServerDoesNotExist, isCatchall, isGreylisting, transientError) do not consume credits. The remaining balance is returned on every response in the `remaining` field.
Free tool daily checks visitor
request ยท day
5
The browser-based free email verifier at /free-email-verifier/ allows 5 checks per day per user before requiring registration for the API free tier (100 credits).
Per-request execution time request
seconds
sub-500ms typical
Published service characteristic. Each response returns an `execution` field with the wall-clock duration of the verification, useful for client-side timeout tuning.

Policies

Credit-First Throttling
The credit balance is the primary throttle. Monitor the `remaining` field returned on every successful response to budget verification work and to top up before hitting zero balance.
Backoff
Honor 429 (throttled) and 503 (service unavailable) responses with exponential backoff and jitter. Retry transient (`status: transient`, `event: transientError`) responses after a short delay rather than immediately.
Auto-Refund
Credits are not consumed for free events or for requests that fail on syntax / DNS / MX. This effectively functions as an auto-refund for non-verifiable inputs.
High-Volume Coordination
For sustained high-throughput verification (bulk list cleanup, cron-driven reverification), coordinate with [email protected] so that platform-side ceilings can be confirmed and lifted if needed.

Sources