mailboxlayer
Email validation API by APILayer — syntax check, MX lookup, SMTP verification, disposable-address and typo detection. Drop-in validation for signup forms.
🟢 Online · 533 ms
100%
Free plan: 100 checks/month, email signup, no credit card
API key
Free alternatives (live ranking)
- Free Dictionary API — 🟢 Online · Unlimited (fair use), no key, no credit card
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- DiceBear Avatars — 🟢 Online · Unlimited (fair use), no key, no credit card
Compare mailboxlayer with…
- mailboxlayer vs Free Dictionary API — Unlimited (fair use), no key, no credit card
- mailboxlayer vs ipify — Unlimited, no key, no credit card
- mailboxlayer vs DiceBear Avatars — Unlimited (fair use), no key, no credit card
Paid alternatives
- ZeroBounce — from $18 per 2k validations
Frequently Asked Questions
Does mailboxlayer require an API key?
Yes, mailboxlayer requires a free API key. You can sign up via https://mailboxlayer.com/documentation.
What is mailboxlayer's free tier?
Free plan: 100 checks/month, email signup, no credit card
Is mailboxlayer currently online?
We check mailboxlayer every hour. The current status is shown at the top of this page. You can also see the 30-day uptime history in the chart above.
Implementation notes
When to use mailboxlayer
mailboxlayer answers 'is this email real?' at signup time: syntax check, MX-record lookup, SMTP mailbox verification, disposable-address detection, and did-you-mean typo suggestions. Wire it into your signup form to cut bounce rates and block throwaway addresses. The free plan (100 checks/month) suits low-traffic forms; bulk list cleaning belongs on a paid plan or a specialist like ZeroBounce.
Common pitfalls
- SMTP verification is slow (2-5s per check) because it actually talks to the target mail server. Run it async after form submit, not inline in the request path — or use `smtp=0` for a fast syntax+MX-only check.
- Big providers (Gmail, Yahoo) accept SMTP probes for addresses that don't exist — `smtp_check: true` is not a guarantee there. Combine with the `score` field rather than trusting one boolean.
- The `did_you_mean` suggestion ('gmial.com → gmail.com') is the highest-ROI field in the response and most integrations ignore it. Surface it as a one-click fix in your form.
Quick start (bash)
curl "http://apilayer.net/api/check?access_key=YOUR_KEY&[email protected]&smtp=1"Embed this badge
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