Fixing Invalid Email Adress

Not every invalid address is a lost contact. Many are typos that a person would fix in two seconds.

The usual suspects

• Domain typos: gmial.com, gmail.con, hotmial.com, yahooo.com.
• Missing parts: no @, no domain extension, spaces at the start or end.
• Wrong separators: commas instead of dots, or two @ signs.
• Old addresses: the mailbox was closed or the person left the company.

Fix at the source

Add a real-time check to your sign-up form. When the domain looks like a typo of a popular one, suggest the correction before the form is submitted.

Fix in a list

Run the list through a verifier. Obvious typos can be corrected in bulk with a find-and-replace on the domain; addresses that stay invalid afterwards should be removed.

Never guess

Do not "repair" an address you cannot confirm. Sending to a guessed mailbox can hit a stranger or a spam trap.

Keep it from coming back

Verify imports, confirm new sign-ups with a double opt-in where it makes sense, and re-check old lists before big campaigns.

A worked example

A newsletter signup list contains `[email protected]`, `[email protected]` and `sam@company,com`.

• `gmial.com` is a typo of gmail.com. The fix is almost certainly `[email protected]`.
• `yahooo.com` is a typo of yahoo.com. Likely `[email protected]`.
• `company,com` has a comma where a dot should be. Likely `[email protected]`.

A verifier flags all three as invalid, and a good one also suggests the likely correction. You still should not rewrite the address silently: if the guess is wrong, you now send to a stranger.

The safe way to apply a fix

1. At the sign-up form, show the suggestion and let the person confirm it.
2. In an existing list, apply a correction only to obvious, high-confidence typos of major providers, and verify the corrected address before sending.
3. For everything else, remove the address or ask the contact to update their details by another channel.

Why it is worth the effort

Each typo is a person who wanted to hear from you and did not. Fixing it at the form recovers that customer. Silently dropping it loses one, and sending to the wrong address risks a spam complaint from a stranger.

Make it routine

Run new sign-ups through a checker as they arrive, and clean older lists periodically with the bulk verifier.

Typos that can be fixed and typos that cannot

A misspelt domain such as "gmial.com" or "hotmial.com" can be corrected with high confidence, because the intended domain is obvious. A mistake in the part before the @ cannot: "john.smith" and "jon.smith" may both be real people. For the second kind, never guess. Ask the person, or leave the address out of the send.

How to log your corrections

Keep a short log of every change: the original value, the corrected value, the date and who approved it. If a customer later says they did not receive anything, the log shows exactly what happened. It also reveals patterns, for example one form that produces the same typo again and again, which tells you where to add a prompt.

Do not auto-correct silently

Showing "Did you mean [email protected]?" and letting the person confirm keeps the data honest. Silent rewriting can attach a message to a stranger's mailbox, which is a privacy problem as well as a delivery problem.

When to give up on an address

If an address bounced hard, do not keep trying; remove it. If a soft bounce repeats for several sends in a row, treat it as dead too. Keeping hopeless addresses only drags your bounce rate and teaches providers that you do not maintain your list.

Teach the people who type

If customers or colleagues enter addresses by hand, a short hint next to the field, such as the expected format, prevents many mistakes. Good form design is the cheapest fix of all.