Email Verification for B2B Outreach: MX and SMTP Checks
Why Verify Before Sending?
Contact information changes as people move roles and companies. An old address may be invalid even when its company record still looks current. Hard bounces and recipient complaints can harm sending reputation, so checks belong before dispatch.
---
The 17Signal Qualification Path
17Signal sources account and contact evidence through Bunlead. The workflow qualifies companies first, then searches for people in current roles at those companies. A person cannot enter a sending batch until the account and role meet the campaign's hard criteria.
- **Account qualification**: Confirm the company fits the current campaign plan.
- **Current-role evidence**: Check that a person still appears to work there.
- **Contact verification**: Use available email evidence and validation signals before sending. Catch-all addresses and uncertain results need extra caution.
- **Suppression check**: Exclude contacts who have opted out or are otherwise ineligible under workspace rules.
Syntax, domain records, and SMTP-level signals can help identify invalid destinations, but none proves that a future message will reach a particular inbox.
---
What Consumes a Credit?
In 17Signal, one outbound credit corresponds to one successfully dispatched email. A contact withheld before dispatch does not consume a sending credit. Teams should monitor actual bounce rates after dispatch and adjust volume or pause a campaign when quality deteriorates.