Free tool — tests your own form only
Is your signup letting fake accounts in?
If your signup form accepts throwaway "disposable" email addresses, anyone can farm free trials, create bot accounts and pollute your data. Test it in 30 seconds — with real throwaway addresses you try on your own form.
Your throwaway test addresses
Real addresses on public disposable-email providers. Fresh each time.
Copy one of the throwaway addresses above.
Go to your own signup form and try to register with it.
Read the outcome below — did the form let it through?
The form accepted it
Anyone with a browser can create unlimited throwaway accounts.
- Free-trial abuse
- Bot signups
- Junk analytics
- Bounces when you email them
Fix: add a disposable check at signup.
The form rejected it
You're screening disposable domains at the form.
- Confirm role-account checks too
- Confirm MX checks too
- Re-test as lists go stale
New throwaway domains appear constantly.
The one-call fix
Check the address at signup and act on the disposable flag. Boundstone also returns MX, role-account and free-provider signals in the same call — and lists what it didn't check, so you know exactly what a pass means.
const r = await fetch("https://api.boundstone.io/v1/verify/email", {
method: "POST",
headers: { authorization: "Bearer bs_live_YOUR_KEY", "content-type": "application/json" },
body: JSON.stringify({ email: signup.email }),
});
const { disposable, mx_found, role_account } = await r.json();
if (disposable) return reject("Please sign up with a permanent email address.");
Questions
What is a disposable email address?
A throwaway inbox from a provider like Mailinator, Guerrilla Mail or YOPmail that self-destructs in minutes. People use them to sign up for things without handing over a real address — which is fine for them, and a problem for you when they're farming free trials or creating fake accounts.
How do I stop disposable signups?
Check the address against a maintained disposable-domain list at the moment of signup, server-side, and block or flag it. Boundstone's email endpoint returns a disposable boolean in one call — you decide the policy. It won't catch a brand-new throwaway domain nobody has catalogued yet, so treat it as a strong filter, not a guarantee.
Does this tool test my site automatically?
No — on purpose. The only way to truly test a signup form is to submit it with a throwaway address, and doing that to someone else's site means creating fake accounts on it (the exact abuse this is about). So this tool gives you real throwaway addresses to try on your own form, and never touches anyone else's.
Early access — free tier is 250 credits/month, forever
The API is live — start free without waiting. This list gets benchmark № 001 the day it publishes. One email. We validate emails for a living — we're not going to spam yours.