Key takeaways
- Treat webhook delivery as at-least-once and make the handler idempotent.
- Verify the signature, acknowledge quickly, and process work asynchronously.
- Use the job status API as the source of truth before creating an export.
- Separate completed, pending, and failed counts so partial work is not presented as final.
- Retry failed notifications without creating duplicate rows or emails.
An email verification webhook is the bridge between a long-running job and the system that requested it. Instead of keeping a browser or server request open while thousands of rows finish, your application receives an event and then retrieves the authoritative status.
Treat events as at-least-once
The same event may be delivered more than once, or events may arrive out of order. Store an event ID or job ID and make each state transition idempotent. A duplicate callback must not create duplicate result rows or send two completion emails.
Secure the endpoint
Verify the provider signature, restrict the accepted methods, apply rate limits, and keep the endpoint separate from unauthenticated application routes. Do not trust a job ID from the body until it has been authenticated and authorized.
Acknowledge quickly
Return a successful response after validating and queueing the event. Do not perform a large export or database rewrite inside the webhook request. Long work belongs in a worker where it can retry safely.
Read authoritative state
Use the job status endpoint or durable result store to confirm completed, pending, and failed counts. A “completed” notification should not be accepted blindly if the result file still has missing chunks.
Notify customers only at completion
Send a completion email after the export has been generated and validated. Include the job name, completed row count, and a link to the dashboard. If only partial results are ready, label them partial and keep the final notification for the actual final state.
VeriMailX supports API and bulk workflows through the developer documentation and bulk checker.
The bottom line
Reliable verification webhooks are signed, idempotent, fast to acknowledge, and backed by an authoritative job status check. They turn long jobs into a recoverable workflow instead of a fragile browser session.
Sources
Frequently asked questions
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