How to Verify Emails Before a Campaign Before a Campaign

You have a list of a few hundred businesses, a campaign written, and a Gmail account ready to go. The worry is simple: how many of these addresses actually work? Send to a pile of dead ones and you get bounce notices, a sending account that starts landing in spam, and no way to tell whether your copy was bad or your list was.

Verifying before you send fixes most of that. Here is how to do it today, in order.

Why bounces hurt more than you think

A bounced email is not just a wasted send. Mailbox providers watch how often your messages hit addresses that do not exist. A high bounce rate looks like the behaviour of someone sending to a bought or guessed list, and that can push your later emails, even to good addresses, toward spam.

There is also a practical cost. If you pay per send or per lead, every dead address is money gone. And your campaign numbers become misleading: a 5% reply rate on a list where a chunk never received anything hides how well your message really did.

Step 1: Clean the file before you verify anything

Verification tools check addresses one by one. Junk in the file means wasted checks. Before running anything:

• Remove duplicates. The same address often appears under two business names, especially from directories.
• Fix obvious formatting. Strip spaces, trailing commas, and text like "mailto:" or "Email:" stuck to the front.
• Delete clearly broken entries. Anything without an @, or with a domain like "example.com" or "yourdomain.com" copied from a website template.
• Split cells with several emails. One row per address makes results easier to act on.
• Remove addresses that have already unsubscribed from you in the past.

If your list came from a spreadsheet or another tool, the full routine is in how to clean a CSV before importing. For past opt-outs, see removing unsubscribed contacts.

Step 2: Run the list through a verifier

A verifier checks, without sending an email, whether the domain accepts mail and whether the specific mailbox appears to exist. You get each address back with a status.

You can use a standalone verification service, or verify inside the tool where you built the list. In GetClient, you can run email verification on a list of leads before you add them to a campaign, so there is no exporting a file to one tool and importing it into another. Credits are used for this, and you can see how that works on the pricing page.

Whatever you use, verify close to your send date. Small business addresses change when staff leave or a business switches email providers, so a list checked three months ago is not a checked list.

Step 3: Sort the results into three groups

Different tools use different labels, but they map to roughly these:

Valid and invalid are easy. The middle group is where judgment comes in.

Handling catch-all and unknown addresses

A catch-all domain accepts mail to any address, so a verifier cannot confirm the mailbox. Many small businesses run on setups like this, so you may see a lot of them.

Some sensible options:

• Keep role addresses on known domains. An info@ or contact@ address found on the business's own website is usually a reasonable bet even if it shows as catch-all.
• Drop guessed personal addresses. If someone built firstname@ by pattern and it comes back unknown, leave it out unless you have another reason to trust it.
• Send to risky addresses in a small separate batch. Put them in their own campaign or segment, send slowly, and watch bounces. If they bounce badly, stop.

A rule of thumb many senders follow is to keep bounces in the low single digits as a percentage. Treat that as a guide, not a guarantee.

Step 4: Check the leads, not just the addresses

An address can be perfectly valid and still wrong for your campaign. While you have the list open, scan for:

• Businesses that have closed or are outside your area
• Categories that slipped in from a broad search (a supply shop in a list of gyms, for example)
• Generic addresses at large chains where your email will never reach a decision-maker

This is where a list built for the right reasons pays off. If you are starting from scratch, how to build a lead list covers picking keywords and locations so you get fewer of these in the first place. Some people also give leads a simple priority score; lead scoring explains the idea.

Step 5: Send carefully, then keep the list clean

Verification lowers risk. It does not remove it. When the campaign starts:

• Start with modest daily volume per sending account, especially on a newer Gmail or domain.
• Watch the first day's bounces. If they are higher than expected, pause and recheck the list.
• Remove hard bounces immediately and never resend to them.
• Honour unsubscribes. Include a clear way to opt out. Rules differ by country, so check what applies to you; this is not legal advice.

In GetClient, campaigns include a one-click unsubscribe link and unsubscribed addresses are skipped automatically on later sends, which saves you maintaining a separate suppression list by hand. For the sending side, see sending cold email from Gmail and building a drip campaign with follow-ups.

A quick pre-send checklist

Before you press start, confirm:

1. Duplicates and malformed rows removed
2. Past unsubscribes removed
3. List verified within the last few days
4. Invalid addresses deleted
5. Risky addresses either removed or separated into their own batch
6. Leads checked for relevance, not just validity
7. Daily sending limits set conservatively

Ten minutes on this list protects the sending account you will rely on for every campaign after this one.