Understand why a delivery failed—and what to do next
Submit an SMTP delivery-error message for classification and a recommended next action. Use the result in your support, retry, and contact-review workflows. Diagnosis costs 5 credits per evaluation.
Understand delivery failures: Classifies the error message you submit and recommends a next action. This does not test mailbox existence or predict a future delivery. Diagnostic text may be processed by a configured external service; see our data-handling notice.
Illustrative response — run a diagnosis to get an API result.
Permanently remove recipient address from mailing lists. Mailbox does not exist or was rejected permanently by the target server.
Turn error messages into a reviewable decision
Bounce diagnostics analyzes information you supply after a failed delivery. It does not predict whether an address will receive a future message.
Classify the supplied error
Review the reported failure category and supporting diagnostic explanation.
Review the next action
Use recommendations such as permanent suppression or transient retry within your own sending policy.
Connect your workflow
Extract diagnostic text from your delivery provider’s events and submit it through the API. Review the documented request shape before integrating.
Practical questions
How is this different from checking an address?
An email check evaluates address and domain signals before a business decision. Bounce diagnosis interprets an error from a delivery attempt that has already failed.
Is diagnostic processing entirely offline?
Do not assume so. The implementation can use an external diagnostic service when configured. Review data handling before submitting diagnostic text or personal data.
Does the result automatically change my contact list?
No. Your application decides how to use the returned recommendation. Review ambiguous or conflicting evidence before suppression or retry.
How is diagnosis billed?
Each bounce diagnosis uses 5 credits per evaluation, drawn from your account’s available allowance or credits. See pricing for plan details.
Review a delivery failure
Try a diagnostic message above, then integrate the API with your own delivery events.