Catch-all and Unverifiable Addresses

When you verify a lead list on import, most addresses come back with a clear answer: the mailbox exists, or it does not. Some do not. This guide explains what those “risky” results mean and how to decide what to do with them.

The three results

Every address you verify lands in one of three buckets:

• Valid. We confirmed the mailbox exists and can receive mail. These are added to your campaign right away.
• Invalid. We confirmed the mailbox does not exist. These would bounce, so they are left out.
• Risky (catch-all or unverifiable). We could not confirm one way or the other. These are held out of your campaign until you decide.

Why some addresses are risky

There are two reasons we can’t confirm an address:

• Catch-all domain. The mail server is set up to accept every address at the domain, even ones that don’t exist. It says “yes” to everything, so its “yes” tells us nothing about whether that specific mailbox is real. Many company domains are catch-all.
• Unverifiable. The mail server didn’t give us a usable answer in time (for example, it was slow, rate-limiting, or temporarily unavailable). This is often temporary, not a sign the address is bad.

We treat both the same way, because in both cases the honest answer is “we don’t know.”

Including or discarding risky addresses

After verification finishes, your campaign’s leads page shows a notice with how many addresses were held, and you get an email pointing you there. Click Review to open the decision, where you choose:

• Discard them. The risky addresses are dropped and never added. This is the recommended default: not sending to unconfirmed mailboxes keeps your bounce rate and sender reputation clean.
• Include them. The risky addresses are added to your campaign. Choose this when you want maximum reach and are comfortable with some uncertainty, or when a large share of your list is held.

How to decide

A few things to weigh:

• Watch your bounce rate. Risky addresses are more likely to bounce than verified-valid ones. A high bounce rate hurts your sender reputation and deliverability, so if you’re already close to your limit, lean toward discarding.
• Look at the proportion. If only a handful of your leads are risky, discarding them costs you little. If a large share of your list is risky (common with catch-all-heavy industries), discarding could throw away most of your reachable audience, and including makes more sense.
• Consider the source. A list from a reputable source with mostly catch-all domains is different from a scraped list full of unverifiable addresses. The first is usually worth including; the second, less so.

Credits

You are charged once for every address we check, whether it turns out valid, invalid, or risky. Including or discarding the risky ones later is free, because you already paid to check them.