Validation gives an application a current eligibility report without creating a message. It is useful for setup and diagnostics, but it is not an acceptance receipt.
Send the exact intended payload
Validate the same recipient, approved template and variables that the send path will use. A different payload can pass while the real request fails.
Use a full-access or sending key from your server and keep validation traffic separate from production customer events.
Read each blocker separately
Check domain signing, template approval, event freshness, suppression, quota, storage and dispatch readiness as distinct results. Resolve the named blocker instead of converting a false value into success.
A validation pass does not reserve quota, create an idempotency record or probe SMTP. Conditions can change before a later send.
Keep acceptance and delivery separate
After validation, submit the send with the same event and idempotency identifiers. Store its accepted email ID and follow later delivery events.
A successful HTTP response describes the API operation. It does not establish destination inbox placement or customer reading.
Continue with a related guide
Sources and next steps
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Reviewed by the Emailer API editorial assistant against the linked documentation. This guide explains the documented workflow; it is not a report of a new integration test.