Free Bulk Email Validator
A list of addresses and a bad feeling about some of them? This bulk email checker validates up to 10 at once and shows which are invalid, which can't receive mail and which come from disposable providers. Free, no signup.
Example results:
| Format | MX Valid | Disposable | Risk Score | Status | |
|---|---|---|---|---|---|
| user@gmail.com | No | 0 | allow | ||
| test@mailinator.com | Yes | 30 | challenge | ||
| nobody@nonexistent.xyz | No | 50 | challenge |
Clean the list before it gets in.
Fidro's API runs these checks on every signup as it happens, so bad addresses never reach your list. 200 validations a month, free.
No credit card required. Cancel anytime.
How it works
Paste your list
Paste up to 10 addresses into the box above, one per line.
Fidro checks each one
Every address gets the same checks: format, mail server and disposable provider, plus a risk score.
Read the verdicts
One row per address, with pass or fail for each check and an allow, challenge or block answer.
What gets checked
Each check catches a different kind of bad address.
Format Validation
Catches typos and broken addresses before they bounce: a missing @, a missing domain, characters that aren't allowed.
MX Record Verification
Looks up the domain's mail servers. No mail server, no delivery.
Disposable Detection
Compares each domain against nearly 10,000 known temporary and disposable email providers.
Risk Scoring
Every check feeds one 0-100 risk score with a plain answer: allow, challenge or block.
Why bad addresses cost you
Every email you send to a dead address bounces, and inbox providers keep count. Bounce often enough and Gmail and Outlook start sending your messages to spam, including the ones meant for real subscribers.
Cleaning the list protects that reputation. Take out invalid addresses, typo domains and disposable inboxes before you send, and more of your email reaches an actual person.
It also saves money. Most email providers charge by list size or by send, so every dead address is something you pay for and get nothing back from.
And it keeps your numbers honest. A list full of throwaway and invalid addresses drags down open rates, click rates and conversions. Take them out and you see how your real audience behaves.
Keeping a list clean
- Validate at collection. Check each address the moment someone signs up. Stopping a bad address at the door beats cleaning it out later.
- Re-validate periodically. Addresses go stale. People change jobs, abandon inboxes and let domains lapse. Run the list through validation every few months.
- Segment by engagement. Split active subscribers from quiet ones. Anyone who hasn't opened in 90 days goes to a re-engagement campaign or off the list.
- Remove hard bounces immediately. A hard bounce means the address will never work. Every extra send to it hurts your sender reputation.
- Use double opt-in. A confirmation email proves the inbox is real and its owner wants to hear from you. It stops most typos and many fake signups.
Frequently Asked Questions
How many emails can I validate at once?
Up to 10 at a time. Paste one address per line and click Validate All. For bigger lists, send each address to Fidro's API from a short script; the free plan covers 200 a month.
What does bulk email validation check?
Three things per address: is it well formed, can its domain receive mail (MX records), and does it come from a disposable email provider. Each one gets a risk score and a plain answer: allow, challenge or block.
How accurate is email validation?
Each layer is a direct check, not a guess. Format checks follow RFC 5322, MX lookups query DNS live, and the disposable list covers nearly 10,000 known providers and refreshes daily. What no validator can promise is that a real, working inbox belongs to a real person.
Why should I clean my email list?
Bad addresses bounce, and bounces teach Gmail and Outlook to send your mail to spam, including the mail meant for real customers. Cleaning the list removes invalid and disposable addresses so your emails land and your numbers mean something.
What happens to invalid emails?
Each one gets a high risk score and a block recommendation, and the results table shows exactly what failed: a bad format, no mail server, or a disposable provider. You decide what to do with each address.
Is this bulk validator free?
Yes, with no signup, for up to 10 addresses at a time and a fair daily limit. For more, Fidro's API has a free plan with 200 validations a month, no credit card.
API
Stop bad addresses at signup.
Cleaning a list is the fix after the fact. Fidro's API checks each address as it arrives, with the IP and network alongside it, and answers allow, challenge or block before the account exists.
Also try our email checker, IP checker, VPN detector, domain checker, and disposable emails database.
curl -X POST https://fidro.io/api/validate \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{"email": "user@example.com"}'Start catching bad signups in the next 5 minutes
Create your account, grab your API key, and send your first request. Free plan with 200 validations/month. No credit card. Cancel anytime.