How to check if an email address is valid: 5 ways

"Valid" is not one test. An address has to pass several, in order, and it can fail at any of them. A good verifier runs all of these.

The first four decide whether an email can be delivered at all. The last two decide whether it's worth sending to. A disposable address will stop working soon. A role-based address is real, but nobody in particular owns it, which makes it a poor target for a one-to-one sales email.

Catch-all domains: valid but unconfirmed

Some companies set their mail server to accept email for any address at the domain, real or not. These are called catch-all or accept-all domains. A verifier asks about jane.doe@ and the server says yes. It also says yes to qwerty123@. So nobody outside the company can confirm the person exists, and the result is "unknown" no matter which tool you use.

Tip: Validation vs verification. People use the words loosely. Strictly, email validation checks that an address is written correctly. Email verification goes further and checks that the domain and mailbox can actually receive mail. An address can pass validation and still bounce.

Every verifier uses slightly different labels, but they all map to these six.

Use these when you have a single address you care about, such as a decision maker you found by hand. They go from the fastest look to the most thorough.

Read the address slowly. Many invalid addresses in a spreadsheet are simple typing mistakes, and you can catch them by eye.

• Exactly one @, with something on both sides.
• No spaces, commas or brackets anywhere.
• No dot at the start or end of the name part, and no two dots in a row.
• A real ending after the last dot, such as .com, .io or .co.uk.
• Common typos in the domain: gmial.com, gamil.com, hotmial.com, outlok.com, or .con instead of .com.

MX records are DNS entries that tell the internet which server receives email for a domain. If a domain has none, mail to it will almost always fail. You can check in a few seconds from your own computer. Open a terminal (Command Prompt on Windows, Terminal on a Mac) and run one of these, swapping in the domain you want to check.

If you see one or more mail server names, the domain can receive email. If you see nothing, or an error that the domain doesn't exist, every address at that domain is invalid. Free web tools called MX lookups show the same thing if you'd rather not use a terminal.

Tip: An MX check tells you about the domain, not the person. A company with perfect MX records will still bounce an address for someone who left last month.

An email verifier does everything above and adds the mailbox check. It connects to the domain's mail server, starts the normal conversation that comes before any delivery, names the address as a recipient and reads the server's answer. Then it ends the conversation before a message is sent. The person never receives anything.

Paste the address into the verifier and read the result against the table above. Most standalone verifiers give a small number of free checks, then charge for each address after that.

Free email verification: what to expect

• Free checks are capped. Expect a handful of single checks a day, or a small one-time allowance, before you're asked to pay.
• Catch-all stays catch-all. No tool, free or paid, can confirm a mailbox on a domain that accepts everything.
• Some servers block checks. Large providers and strict corporate servers sometimes refuse to answer, which gives you "unknown".

Put the exact address in quotes and search Google. If it shows up on the company's own site, in a press release, in a conference programme or in an author bio, a real person published it. That's good evidence, especially for catch-all domains where a verifier can't help.

Also check that the person still works there. Open their LinkedIn profile or the company's team page. Addresses for people who have since moved on are a common cause of bounces. If you're building the address from a company's email format, how to find someone's email walks through it with a worked example.

For one important address, you can simply send the email you meant to send and watch your inbox. A hard bounce usually comes back within minutes, with a message saying the address doesn't exist. No bounce after a day is a good sign, though not proof: catch-all domains accept first and sometimes bounce later.

Only do this one address at a time, and only with a real, relevant message. Sending to a list to see what bounces is exactly what damages your sender reputation.

The single-address methods don't scale past a few rows. For a list, clean it in a spreadsheet first, then verify it in bulk.

1. Remove duplicates. Sort by the email column and delete repeats, so you don't pay to check the same address twice.
2. Fix or delete obvious syntax errors. Filter for cells without an @, with spaces, or ending in .con.
3. Upload the file to a bulk verifier. It returns each row with a result: valid, invalid, catch-all, unknown, disposable or role.
4. Delete invalid and disposable rows. They will only ever bounce or vanish.
5. Remove role inboxes from a cold outreach list. Keep them only if your message is meant for whoever reads the shared box.
6. Split out catch-all and unknown rows. Send them later, in a small separate batch, and stop if they bounce.
7. Add a status column and mark every bounce from now on. That column becomes your do-not-send list.

The rest of a pre-send clean-up, like removing competitors, customers and wrong job titles, is in clean a list before you send.

If the list is old, refresh it instead

Verifying an old list tells you which emails are dead. It doesn't tell you where those people went. People change jobs all the time, so a list that was clean a year ago can be full of former employees (how fast contact data goes stale explains how quickly that happens).

If your list has the person's LinkedIn profile URL, or their name and company domain, upload it to ContactYard Enrich Contacts. Map the columns, run it, and download the file with fresh, verified work emails and mobiles filled in. You get current addresses instead of a pile of deletions. Step by step: fill missing emails and phones in a spreadsheet.

A bounce is an email that couldn't be delivered. There are two kinds, and only one counts against your list.

Aim to keep hard bounces under about 2% of the emails you send. That's a widely used rule of thumb. Many cold email senders treat 3% as the point to stop and check the list, because mailbox providers read a high bounce rate as a sign you don't know who you're mailing, and more of your good emails start landing in spam.

If you're already over that line, the five usual causes and how to tell them apart are in why your bounce rate is over 3%.

Every method above is a repair job on data that should have been right in the first place. The faster route is to start with emails that are already verified.

That's how ContactYard works. Every work email is verified before you get it, and the verification is included in the same single credit as the email and the mobile number when available. There's no separate verifier subscription, no second upload and no second bill. Data is refreshed every 30 days, so you aren't checking addresses that went stale last quarter.

On the Scale plan that works out to about $3.30 per 1,000 verified contacts. Build a list by job title, company domain, headcount, industry and location, export it, and send. If you want to see the quality for yourself before you commit, test a contact data provider shows a fair way to compare. Or just start free and check a sample.

How do I verify if an email address is valid?

Run it through an email verifier. It checks the syntax, confirms the domain has MX records, and asks the mail server whether the mailbox exists without sending anything. Valid means send, invalid means delete, and catch-all or unknown means treat it as a guess. You can also look up MX records yourself, search for the exact address on Google, and confirm the person still works at the company.

Is there a free email validity checker?

Yes. Most email verifiers give a small number of free checks before they charge per address, and MX lookup tools are free. For outreach lists, ContactYard skips the step: every work email is verified before you get it, and the verification is included in the one credit you pay for the contact.

Can you check if an email address is valid without sending an email?

Yes. A verifier connects to the domain's mail server, names the address as a recipient and reads the answer, then ends the conversation before any message is sent. The person receives nothing. The one exception is catch-all domains, which say yes to every address, so no check can confirm them.

What does catch-all mean in email verification?

A catch-all, or accept-all, domain accepts mail for any address, real or made up. A verifier can't tell whether the person exists, so the result is risky or unknown. Send to these addresses in a small separate batch and stop if they bounce.

What is a verified email address?

In outreach, it's an address a verifier has confirmed can receive mail: correct syntax, a working domain and a mailbox the server accepts. On websites and apps, a verified email address means the owner clicked a confirmation link to prove the inbox is theirs.

How do I check a list of emails?

Remove duplicates and obvious typos, upload the file to a bulk email verifier, then delete invalid and disposable rows, drop role inboxes from cold outreach, and send catch-all rows separately. If the list is old and has names with company domains or LinkedIn URLs, upload it to ContactYard Enrich Contacts to get fresh verified emails instead.