Email Verification for SaaS
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Every SaaS product with a self-serve signup form has the same quiet problem. A share of the people entering your funnel are not people at all, or they are people who never intended to come back. They typed a throwaway address to get past the gate, grabbed the free asset or the trial, and left. Your product analytics do not know that. Your activation dashboard counts them. Your onboarding sequence emails them for the next fourteen days.
The damage is not just wasted sends. It is that the numbers you steer the company with quietly become fiction. Trial-to-paid conversion looks worse than it is because the denominator is full of accounts that were never real. Activation rate drops and nobody can explain why. Product-qualified lead scoring fires on accounts that will never respond. And meanwhile your onboarding drips are hammering addresses that do not exist, which is exactly the behaviour mailbox providers use to decide whether your product emails belong in the inbox or in spam.
Why signup forms attract bad addresses
Disposable inbox services exist precisely to defeat email gates. They are free, they take five seconds, and they are extremely popular with anyone who wants your trial without a relationship. Mailthentic maintains detection for over 800 disposable and temporary email domains, so those addresses are identified at the moment of signup rather than three weeks later when your password reset bounces.
The second category is subtler: typos. Someone genuinely wants your product and mistypes their work domain. That account can never be recovered, never verify their email, never receive the invoice. A real-time syntax and MX check at the form catches it while the user is still on the page and can fix it.
What honest verification looks like
Some SaaS vendors promise to confirm every mailbox. That is not possible, and pretending otherwise is how teams get burned. If a signup uses a Gmail, Google Workspace, Outlook or Microsoft 365 address, those providers return a 250 OK during an SMTP check even for mailboxes that do not exist, because they deliberately block address harvesting. If a domain is configured as catch-all, it accepts every address by design, so no verifier anywhere can confirm one individual mailbox on it.
Mailthentic tells you that. You get the status, the reason, the SMTP response code and a confidence score, so you can decide what to do with an ambiguous result instead of being handed a false valid.
- Real-time API for the signup form itself, so bad addresses never enter the database.
- Bulk CSV upload for the historical user table you have never cleaned.
- Role account flagging across more than 150 prefixes, so you can see when a trial was started by info@ rather than a human.
- Catch-all and greylisting handled honestly, with temporary deferrals retried rather than thrown away.
The SaaS deliverability challenge
Disposable addresses pollute your trial funnel
Throwaway inboxes are free and instant, and they are the standard way to get past an email gate. Every one of them becomes a trial account, an onboarding sequence, and a line in your conversion math that will never convert.
Activation and conversion metrics quietly lie
When the denominator is full of accounts that were never real people, trial-to-paid and activation rates read low and nobody can say why. You end up optimising onboarding against a number that is mostly noise.
Onboarding drips damage your sending reputation
A fourteen-day welcome sequence firing at dead addresses is a sustained stream of bounces. Mailbox providers read that as a sender who does not manage their list, and your genuine product emails start landing in spam.
Typos lock real customers out permanently
A user who mistypes their work domain can never confirm their email, never reset their password, and never receive an invoice. They churn silently and you record it as a failed trial rather than a broken address.
How Mailthentic helps SaaS teams
Verify at the point of signup
The real-time API checks syntax, domain, MX records and disposable status while the user is still on the form. Bad addresses are stopped before they create an account, and typos can be corrected on the spot.
Detect throwaway inboxes by name
Mailthentic identifies over 800 known disposable and temporary email domains. You can block them outright, route them to a restricted trial, or simply tag them so they never distort your reporting.
Clean the user table you already have
Upload your existing user and lead list as a CSV. Duplicates are removed before processing, so you are not charged for them, and every row comes back with a status, a reason, an SMTP code and a confidence score.
Separate humans from shared mailboxes
Over 150 role-based prefixes such as info@, admin@, support@ and billing@ are flagged. A trial started by a shared inbox is a different sales conversation from one started by a named user, and now you can tell them apart.
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Fewer fake and disposable accounts entering your trial funnel
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Activation, trial-to-paid and PQL metrics based on real users
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Protected sending reputation for transactional and lifecycle email
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Real customers rescued from typos before they are locked out
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Honest reporting on catch-all and provider-ambiguous addresses instead of guesses
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A real-time API for signup plus bulk CSV cleaning for your existing database
Frequently asked questions
Can I verify an address at the moment of signup without slowing the form down?
Will this stop every fake signup?
Why does a Gmail or Microsoft 365 address come back as unconfirmed?
What is a catch-all domain and why does it matter for B2B signups?
Should I block role addresses like info@ from my trial?
Can I clean my existing user database as well as new signups?
More Industries
Reach the inbox in SaaS
Start with 1,000 free verification credits. No credit card required.