Verification Control

Balance Speed with Accuracy - On Your Terms

Impressionwise offers optional account-level parameters that allow you to control the speed of email verification, with processing windows ranging from as fast as 4 hours up to a maximum of 48 hours. This flexibility enables you to prioritize faster turnaround when timelines are tight - without forcing a one-size-fits-all approach.

How Speed Settings Impact Verification Results

Email verification accuracy is directly influenced by the time allocated to observe, analyze, and validate deliverability signals across mail servers, domains, and behavioral patterns. Processing speed can therefore affect the reliability of classifications, especially for challenging email addresses such as Accept-All domains, greylisted addresses, or rate-limited servers.

The table below summarizes the relationship between verification speed, processing depth, and expected confidence in results:

Processing Speed	Time Frame	Impact on Verification
Fast	4–12 hours	Limited observation; fewer retries; may yield lower confidence for Accept-All or greylisted domains. Quick insight for large volumes; may sacrifice some accuracy.
Standard	24 hours	Balanced depth of analysis; sufficient retries; higher confidence classifications. Recommended for general usage; balances speed and reliability.
Extended	48 hours	Maximum signal collection; multiple retries; highest confidence classifications. Maximum accuracy and reliability; ideal for high-value or high-risk campaigns.

For optimal results, we generally advise using Standard or Extended processing (24–48 hours) for when campaign accuracy is mission-critical. Fast processing is suitable for non-critical use cases where speed is prioritized over absolute accuracy.

Important Considerations

While accelerated verification can deliver results more quickly, it may introduce tradeoffs.

It’s a matter of Speed versus Accuracy

Reduced Confidence for Challenging Domains. Addresses associated with Accept-All domains, greylisted domains, or slow-responding mail servers may have lower confidence.
Impact on Deliverability and Reputation. For campaigns where email deliverability, sender reputation, and precise targeting are critical, longer processing windows are recommended. Extended processing allows for additional observation, signal collection, and retries, resulting in higher-confidence classifications.
Reduced Confidence for Challenging Domains. Addresses associated with Accept-All domains, greylisted domains, or slow-responding mail servers may have lower confidence classifications when processed at accelerated speeds.
Higher Incidence of Unknown or Risk Classifications. Quick processing may result in a larger proportion of addresses being classified as unknown, risky, or temporary undeliverable, as there is less time to observe and validate all deliverability signals.
Limited Retry Opportunities. Certain servers intentionally delay responses (e.g., throttling or greylisting). Faster verification may limit retries, reducing the opportunity to accurately resolve these delayed responses.
Impact on Deliverability and Reputation. For campaigns where email deliverability, sender reputation, and precise targeting are critical, longer processing windows are recommended. Extended processing allows for additional observation, signal collection, and retries, resulting in higher-confidence classifications.

For campaigns where deliverability precision and reputation protection are critical, longer processing windows are recommended.

Designed for Flexibility

Verification speed controls are optional and can be configured based on your specific use case—whether you need rapid results for time-sensitive campaigns or maximum accuracy for high-value lists.

Stop wondering and start knowing if your emails are truly deliverable and contact us today.