Getting SMTP results in Zapier — avoiding timeouts

How SMTP verification works in Zapier

When you use the Validate Email or Validate Email and Get Routing Decision actions in Zapier, BounceProtect runs SMTP verification in the background. SMTP verification confirms whether a specific mailbox actually exists at the mail server — it is the most accurate signal in the validation pipeline.

For most emails, SMTP results come back within a few seconds. For some domains — particularly those behind security gateways like Proofpoint or Mimecast — the SMTP check can take 30 to 90 seconds.

BounceProtect's Zapier integration automatically waits up to 90 seconds for SMTP results before returning. In most cases this is fast enough and you will see a complete result with smtp_result showing Accepted, Rejected, or Inconclusive.

When you might see incomplete results

If you are on a free Zapier plan, individual Zap steps have a 30 second execution limit. If SMTP takes longer than 30 seconds for a particular domain, the action will return with smtp_result showing Not Checked or Pending. The email status and send recommendation will still be based on all other signals — MX records, domain age, spam risk, catch-all detection — just without SMTP confirmation.

For most use cases this is still accurate enough to make a routing decision.

Option 1 — Use the bulk flow for full SMTP results

If you need guaranteed SMTP results for every email, use the bulk validation flow instead of single email validation:

1. Trigger — your source app (HubSpot, form, etc.)
2. Action: BounceProtect — Validate Emails (Bulk) — submit the email, returns an upload_id
3. Action: Delay by Zapier — wait 2 minutes
4. Search: BounceProtect — Get Validation Results — pass the upload_id
5. Action: your destination app — use the fully verified results

This approach decouples the SMTP wait from the Zap step timeout entirely. The 2 minute delay gives the SMTP worker time to complete verification before you fetch the results.

Option 2 — Use the routing decision without SMTP

For real-time lead routing where speed matters more than SMTP confirmation, use Validate Email and Get Routing Decision. The routing decision (SEND, SEND WITH CAUTION, REVIEW, DO NOT SEND) is based on all available signals including domain infrastructure, spam risk, catch-all detection, and role account detection. SMTP confirmation upgrades a result from SEND WITH CAUTION to SEND for borderline emails, but the routing decision is actionable without it.

Most false positives in outbound campaigns come from catch-all domains and role accounts, not from SMTP-unverified addresses. The routing decision handles these correctly regardless of SMTP status.

Option 3 — Filter on smtp_checked

If you want your Zap to only proceed when SMTP verification has completed, add a Filter step after the Validate Email action:

1. Action: BounceProtect — Validate Email
2. Filter by Zapier — only continue if smtp_checked equals True
3. Your destination action

This stops the Zap for emails where SMTP did not complete in time. You can handle those separately with a different Zap path or simply let them through your normal process without validation.

Reading the smtp_result field

The smtp_result field returns one of the following values:

Accepted — the mail server confirmed the mailbox exists. Highest confidence signal for deliverability.

Rejected — the mail server confirmed the mailbox does not exist. Safe to remove from your list.

Inconclusive — SMTP was attempted but the server gave an ambiguous response. Common with catch-all domains and security gateways. Use the send_recommendation field to decide.

Not Checked — SMTP verification has not run yet. The result is based on DNS and domain signals only.

Pending — SMTP is queued and will run shortly. Use the bulk flow with a delay if you need the completed result.