How to verify business email addresses before outreach

Written by the Lusha content team. Lusha facts come from our documentation, linked in Sources. The live example was run through the Lusha connector on November 15, 2026.

To verify business email addresses before outreach, run two checks. The first asks whether the mailbox exists and accepts mail. The second asks whether the address still belongs to the person you mean to reach, in the job you think they hold. A list that passes only the first check can still send part of your campaign to people who left.

This guide explains how each check works, gives a six step routine for any list, and shows five emails checked live with what came back for each one.

Key takeaways

• Verification is two checks, not one. A mailbox check confirms the address accepts mail. A person check confirms who is behind it.
• A valid mailbox can be the wrong mailbox. Companies leave old inboxes open or forward them. The email delivers and nobody you wanted reads it.
• Check the domain against the employer. In our live run one of five work emails carried the top confidence grade and sat on a domain that differs from the company website. That is a question to settle before sending.
• Grade and date beat a yes or no. A confidence grade and the date an email was last verified let you set your own bar.
• Verify close to the send. People change jobs every month, so a list verified in spring is a different list by autumn.

Why verify business emails before outreach

• Bounces cost you the next send. Mail providers watch how many of your emails bounce. A bad list today pushes good emails to spam tomorrow.
• People move. Lusha measured that 12.25% of US sales leaders at VP and C level changed roles in 12 months. The method and the full numbers are in the B2B data decay study. Every one of those moves turns a correct email into a wrong one.
• Wrong person, wasted touch. An email that lands in a former employee’s forwarded inbox counts as delivered in your report and does nothing for your pipeline.

The two checks: mailbox and person

How a mailbox check works

1. Format. The address has one @, a valid domain and no illegal characters.
2. Domain. The domain exists and has mail records that say where its email goes.
3. Mailbox. The verifier opens a conversation with the mail server and asks whether it would accept mail for that address, then hangs up without sending anything.
4. Catch all. Some servers say yes to every address, real or not. The verifier flags these as accept all, which means unknown, not valid.
5. Risk flags. Shared inboxes such as info@ or sales@, throwaway domains and addresses with a history of complaints are marked.

The result is a status per address: valid, invalid, accept all or unknown. Send to valid. Drop invalid. Decide on the rest with the person check.

What a mailbox check cannot tell you

• Whether the person still works there. Many companies keep a mailbox alive for months after someone leaves.
• Whether it is the right person. A valid address for a different J. Smith is still valid.
• Anything about accept all domains. Large companies often run them, so the accounts you care about are the ones that come back unknown.
• Whether the title on your list is current. A promoted buyer needs a different message at the same address.

How to verify business emails before outreach in six steps

1. Clean the list. Remove duplicates, fix obvious typos in domains, and drop shared inboxes unless you mean to write to them.
2. Check the person. For each contact, confirm the current employer and title. Anyone who left comes off the list or gets replaced by the new owner of the role. Run it: validate emails before a campaign.
3. Match the domain. The email domain should match the domain of the company the person works for now. A mismatch is not always wrong, because companies run more than one domain, but it earns a second look.
4. Keep by grade and date. Send to the highest confidence grade first. Treat old verification dates and lower grades as a separate, smaller batch.
5. Run a mailbox check on what is left. Do this for lists you did not source yourself, such as event signups, and for anything older than a quarter.
6. Send in batches and watch the bounces. Start with a slice of the list. If bounces stay low, send the rest. Suppress every address that bounces so it never gets a second try.

For one address at a time, use verify a B2B email before sending. If an email already bounced, use find the right email address after a bounce.

A live example: five emails and what came back with each

We asked the Lusha connector in Claude for senior contacts with a work email at two US software companies, then revealed the emails for five of them. Each email came back with a type, a confidence grade and the date it was last verified, next to the person’s current title and the date they started the role.

Contacts confirmed live via Lusha connector, November 15, 2026. People are shown by initials, and the companies and email addresses are masked. All five emails carried an update date of November 15, 2026. Grades are shown as the connector returned them.

What the run showed:

• The person check came with the email. Title and start date arrived in the same result, so there was no second lookup to confirm the person is in the seat. One contact started the role eight months ago, which a list built last year would have missed.
• A top grade did not end the checking. S.H. has an A+ work email on a domain that is not the company website domain. It may be a second company domain. It is still the row to confirm before a send, and the reason step three exists.
• Work and personal addresses were labelled. A personal address also came back for each person, marked private. Those stay out of a business campaign.
• Every email had a date. You can sort a list by when each address was last verified and re check the oldest first.
• The cost was visible. The search used one credit and the five emails used five.

Bulk lists, CRM cleanup and checks at the form

• A bulk list before a campaign. Run the six steps on the whole file and keep a column for the send decision: send, switch to a newer address, hold or skip. The Campus guide how to clean a B2B contact list before a campaign has the prompt.
• CRM records. Emails in a CRM age in place. Re check contacts on a schedule and when a deal reopens. Lusha CRM Data Enrichment updates Salesforce records through field mapping, and the Campus templates for HubSpot and Salesforce run a verification pass before a campaign goes out.
• New signups. A form needs a mailbox check at the moment of entry, to catch typos and throwaway addresses while the person is still on the page. That is a job for an email verification tool with an API.

Where Lusha fits, and where a verifier fits

Lusha documentation says email addresses are validated and given a confidence score, which is shown with the email when you reveal a contact. Each email also carries its type and the date it was last verified, and the contact record carries the current company and title. That covers the person check and grades the address in one step, inside the Lusha Workspace, the API, and Claude or ChatGPT through the Lusha MCP. Lusha publishes its email accuracy figure on its data page.

The documentation does not describe a standalone checker for addresses typed into your own forms. For those, use an email verification tool at the form, and use Lusha to confirm who the person is before sales writes to them. The two answer different questions, and a careful team runs both.

FAQ

How do you verify a business email address before outreach?

Run two checks. A mailbox check confirms the address exists and accepts mail. A person check confirms the address belongs to the person you mean to reach, at their current employer and in their current role. Send to addresses that pass both.

How do you validate business emails in bulk?

Clean the file, check each person against a B2B data provider, match each email domain to the current employer, keep the highest confidence grades, run a mailbox check on the rest, and send in batches while watching bounces.

Does a verified email mean it will not bounce?

No. Verified means the address passed a check on a certain date. Mailboxes close and people move after that date, so verify close to the send and look at the date on each address.

What is a catch all or accept all email domain?

A domain whose mail server accepts mail for any address, real or not. A mailbox check cannot confirm individual addresses there, so the result is unknown. A person check is the way to decide whether to send.

What is the difference between an email finder and an email verifier?

An email finder returns an address for a name and a company. An email verifier checks whether an address you already have accepts mail. A B2B data provider such as Lusha returns the address with a confidence grade, a date and the person’s current role.

How often should you re verify a contact list?

Before every campaign, and at least once a quarter for records that sit in a CRM. Job changes are the main reason a good address goes bad, and they happen every month.

Related: What tools find verified emails at scale? and the data accuracy FAQ.

Sources

All pages accessed November 15, 2026.

• Lusha docs: Understanding data quality and coverage
• Lusha docs: Email confidence ratings
• Lusha docs: Data Catalog
• Lusha docs: CRM Data Enrichment
• Lusha: B2B data decay study