Email Domain Checker
Not sure about the domain in a signup email? Check it here: whether it can receive mail, whether it belongs to a disposable email provider, and how risky it looks. Free, no signup.
Need this in your signup flow?
Run the same check in your signup form with Fidro's API. 200 a month free, no credit card.
gmail.com
Risk score0 / 100
allowDisposable
- Not disposable
Mail Server
- MX records found
MX Records
| Priority | Mail Server |
|---|---|
| 5 | gmail-smtp-in.l.google.com |
| 10 | alt1.gmail-smtp-in.l.google.com |
| 20 | alt2.gmail-smtp-in.l.google.com |
| 30 | alt3.gmail-smtp-in.l.google.com |
| 40 | alt4.gmail-smtp-in.l.google.com |
A Records
- 142.251.30.18
- 142.251.30.19
- 142.251.30.17
- 142.251.30.83
Check every signup, not just this one.
Fidro's API checks the whole email on every signup, adds IP and VPN checks, and answers allow, challenge or block. 200 lookups a month, free.
No credit card required. Cancel anytime.
How it works
Type a domain
Type any domain, like the part after the @ in a signup email.
Fidro checks it
Fidro looks up the mail servers and A records and compares the domain against its disposable email list.
Get a verdict
A risk score, the DNS records it found, and a plain answer: allow, challenge or block.
What the checker looks at
Three questions that tell you whether a real person could have an inbox here.
Disposable Detection
Is the domain one of nearly 10,000 known temporary and disposable email providers?
MX Record Verification
Does the domain have mail servers? If not, nobody can receive email there.
DNS Resolution
Does the domain point at real servers? A domain with no A records is often parked or abandoned.
Risk Scoring
The answers add up to one 0-100 risk score with a plain answer: allow, challenge or block.
How disposable email domains work
A disposable email service registers domains and points them at a mail server that accepts anything sent to any address there. Mailinator, Guerrilla Mail and 10MinuteMail hand out an inbox in seconds: no registration, no verification, no real identity.
Some use one well-known domain. Others rotate through hundreds or thousands to stay off blocklists, and the clever ones register new domains all the time. That's why a list you made once goes stale. Fidro tracks nearly 10,000 disposable domains and refreshes the list daily.
For a business, they mean free tier abuse (one person, endless trial accounts), fake signups that inflate your numbers, spam and bots, and a quiet way around email verification. Check the domain at signup and the throwaway address never gets in.
Why check an email domain
Clean data. Signups from disposable or broken domains fill your database with people you can never reach. They inflate your user count, skew your analytics and never convert. Checking the domain at signup means every address belongs to an inbox that works.
Fraud. Disposable domains are one of the clearest signs of an account nobody intends to keep: free tier farming, promo code abuse, fake reviews. Blocking them at registration is one of the cheapest defences there is.
Deliverability. Email to a domain with no mail server bounces, and Gmail, Outlook and Yahoo all keep count. Bounce too often and your real customers' email starts landing in spam. Checking the domain first keeps your sender reputation intact.
Reachable customers. In finance, healthcare and e-commerce you often need a way to reach every customer. A domain check won't verify who someone is, but it does confirm the address they gave you can receive mail.
Frequently Asked Questions
What is domain reputation?
For signups, it comes down to whether you can trust an email address at that domain. A domain with working mail servers and no link to a temporary email service is a normal place for a real person to have an inbox. A domain run by a disposable email service, or one that can't receive mail at all, is a reason to look twice.
How do I check if a domain is safe?
Type the domain into this checker. Fidro looks up its mail servers (MX records) and its A records, compares it against nearly 10,000 known disposable email providers, and gives you a risk score from 0 to 100. A low score means a normal email domain; a high one means no mail server or a throwaway provider.
What is a disposable email domain?
A domain run by a temporary email service like Mailinator, Guerrilla Mail or 10MinuteMail. Anyone can grab an inbox there without giving real details, and it's gone a few minutes later. That's why it's the domain of choice for free tier abuse, spam accounts and getting past email verification.
What are MX records?
MX (mail exchange) records are the DNS entries that say which servers receive email for a domain. No MX records means the domain can't receive email, which is a red flag for any address you're about to accept. Each record has a priority, and the lowest number is tried first.
Why should businesses check domain reputation?
To keep fake accounts out and email deliverable. Blocking disposable and broken domains at signup cuts fake accounts, free tier abuse and spam, and it protects your sender reputation because you only ever email domains that can receive mail.
Is this domain checker free?
Yes, with no signup and a fair daily limit. For the same check in your own signup flow, Fidro's API has a free plan with 200 lookups a month, no credit card. Paid plans start at $29 a month for 5,000.
API
Put this check in your signup form.
One API call checks the whole email (format, mail servers, disposable provider) alongside the IP, and answers allow, challenge or block before the account exists.
Also try our email checker, IP checker, VPN detector, bulk email checker, and browse the disposable emails database.
curl -X POST https://fidro.io/api/domain-lookup \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{"domain": "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.