mailboxlayer and validateemail.io at a glance
| Feature | mailboxlayer | validateemail.io |
|---|---|---|
| Syntax and MX checks | Yes | Yes |
| SMTP check | Yes | No. It's on our roadmap. |
| Catch-all detection | On paid plans | No |
| Disposable, role and free provider flags | Yes | Yes |
| Typo suggestion | Yes (did_you_mean) | Yes (did_you_mean) |
| Quality score | Yes | Yes, plus a status and reason |
| Authentication | Access key in the URL query string | Bearer token or X-API-Key header; a query parameter also works |
| HTTPS | Their FAQ describes HTTPS access as a paid-plan feature | Always HTTPS |
| Free use | A free plan with a small monthly request quota | The free email checker on this site; no free API plan yet |
| Pricing | Monthly plans | Pay as you go at £0.002 per email, or a custom Enterprise plan. Opening soon. |
When mailboxlayer is the better choice
Choose mailboxlayer if you need an SMTP check today, or catch-all detection, or if you want a free API plan you can call from code right now. We don't have any of those yet.
When validateemail.io fits better
validateemail.io is built for the sign-up form: one quick request when the user submits, and an answer you can act on in code.
- Every response includes the result of each check next to the verdict, so you can set your own policy. A B2B form might accept role addresses like
sales@but block disposable ones. - Typo suggestions know which domains each provider really uses.
gmial.combecomesgmail.com, while real regional domains likeyahoo.deandhotmail.itare left alone. - The API runs on Cloudflare's network and caches domain lookups, so checks on popular domains don't wait on DNS.
- You can run the full set of checks in the free email checker before you sign up for anything.
Switching from mailboxlayer
The responses are similar enough that switching is mostly renaming fields:
| mailboxlayer field | validateemail.io field | Notes |
|---|---|---|
format_valid | checks.syntax | |
mx_found | checks.mx_found | |
smtp_check | checks.smtp | Always null for now. |
catch_all | No equivalent | |
role | checks.role_based | |
disposable | checks.disposable | |
free | checks.free_provider | |
did_you_mean | did_you_mean | A full corrected address, or null. |
score | score | The two scores are calculated differently, so don't reuse old thresholds. Branching on status is simpler. |
access_key parameter | Authorization: Bearer header | A header keeps the key out of server logs and browser history. |
The API reference lists every status and reason, and the guides for Node.js, Python and PHP show complete integrations.
Frequently asked questions
Is there a free validateemail.io API plan?
Not yet. You can use the free checker on this site without an account. The API will be pay as you go at £0.002 per email, and keys go to people who register interest as plans open.
Does validateemail.io check whether the mailbox exists?
Not yet. We confirm that the domain exists and has working mail servers. Mailbox-level checks are on the roadmap, and the response already has a checks.smtp field that stays null until then.
Can I keep sending the key in the URL?
Yes, the api_key query parameter works for quick tests. In production, send it in a header so it doesn't end up in logs.
mailboxlayer is a trademark of its owner. This page isn't affiliated with or endorsed by mailboxlayer. Details come from mailboxlayer's public website and documentation as of October 2026, so check their site for current features and prices. We also compare validateemail.io with ZeroBounce and NeverBounce.