Catch-all emails: what they are and how to send to them safely

You run a list through an email verifier and a chunk of it comes back neither valid nor invalid, but “catch-all”, “accept-all” or “risky”. That chunk is often large, and it is where most surprise bounces come from. This guide explains what a catch-all address is, why verification can't settle it, how much risk it adds, and how teams handle it in practice.

What a catch-all address is

A catch-all domain is a mail domain whose server accepts mail for any address at that domain, whether the mailbox exists or not. Some companies set this up on purpose so that no message to a misspelled name gets lost. Others end up with the same behaviour because their mail security setup accepts every message first and only decides later what to deliver.

An email verifier normally checks an address by asking the receiving mail server whether that mailbox exists, without sending a message. On a catch-all domain the server says yes to every address, so the answer means nothing. The verifier can tell you that the domain is real and accepts mail. It cannot tell you whether jane.doe@ actually reaches Jane.

How common catch-alls are

Estimates vary with the data source, but they are consistently high. Published figures from verification vendors and outbound agencies in 2026 range from about 20 percent of B2B addresses to 30 to 50 percent of otherwise valid B2B contacts. Enterprise domains tend to sit at the higher end. In other words: in a typical B2B list, catch-alls are not an edge case.

How much risk they add

Unverified catch-all addresses bounce noticeably more often than verified ones. Figures published by outbound agencies put the bounce rate of unchecked catch-alls at around 5 to 12 percent; some vendors cite even higher numbers. That matters because the thresholds are tight: most deliverability guidance aims for a total bounce rate below 2 percent, and Instantly pauses a campaign automatically at 5 percent by default.

A quick illustration: if 30 percent of a list are catch-alls and 8 percent of those bounce, the catch-alls alone add 2.4 percentage points to the bounce rate of the whole send. Everything else can be perfectly verified and the campaign still lands above the 2 percent line.

Four ways to handle catch-alls

1. Send them separately. Keep verified addresses on your main sending domains and send catch-alls from separate domains or mailboxes. If they bounce more, your main domains are not affected.
2. Let them in only on good grounds. Accept a catch-all when it comes from a trusted source and the person and role are plausible, not when the address is a pure pattern guess like firstname.lastname@ with no other evidence.
3. Use a specialist check. Some services focus on catch-alls and try to resolve them with sending history or other signals instead of the standard mailbox check. Their accuracy figures come from the vendors themselves, so test them on a sample of your own data first.
4. Combine two verifiers. A second opinion reduces the number of addresses that end up as “unknown”, although it cannot turn a true catch-all into a confirmed mailbox.

What not to do: treat catch-all as valid and send it in the main campaign, or throw all catch-alls away. The first risks your domain, the second can cost you a third of your best accounts.

A practical rule set for cold email

• Invalid, disposable, role-based (info@, sales@) and typo addresses: remove before sending.
• Valid: send, but re-verify if the check is older than about 30 days, since B2B data decays by roughly two to three percent per month.
• Catch-all: separate segment, separate domains or a specialist check, never mixed into the main campaign.
• Unknown or error: re-run the check later; treat as unverified until then.
• Watch the whole list, not only single rows: if the expected bounce rate is above 2 percent, fix the list before you send.

How ListPlus handles it

ListPlus runs free format checks on every email column automatically, including role-based addresses, disposable domains, typos and test domains. The paid deliverability check costs 0.1 credit per address and asks the mail server directly. It returns catch-all as its own result, separate from valid, and a catch-all result is not charged. Treat it as unconfirmed: filter on it and send those contacts as a separate segment.