Know if an email is real before you send

What is email verification?

Email verification is the process of checking whether an email address is valid, correctly formatted, and likely to receive mail. It typically includes syntax validation (RFC 5322), checking whether the domain has a mail server (MX record), detecting disposable or role-based addresses, and, in full verifiers, an SMTP handshake to confirm the specific mailbox exists. Verification reduces bounce rates and protects sender reputation.

EmailVerifyerAPI currently runs six checks entirely in your browser: syntax validation (RFC 5322), disposable domain detection, role-based address detection, free-mail provider detection, a catch-all domain heuristic, and did-you-mean typo correction. MX record lookup and SMTP handshake verification are planned for the upcoming API and are not yet available.

Email industry benchmarks

• About 22% of marketing email addresses go invalid each year (HubSpot, 2024).
• Bulk senders must keep spam-complaint rates below 0.3% (Google & Yahoo, February 2024).
• An estimated 15% of unverified lists contain invalid addresses (industry estimate).

Your list is losing value right now, quietly

People change jobs, domains expire, inboxes get abandoned - and every month, something like 1 to 2% of your list quietly goes bad. Most senders only notice once the damage is done: Gmail starts filtering their messages, or an ESP flags the account for review.

Email verification catches the obvious invalids before you send. It won't fix every deliverability problem, but removing hard bounces, disposable inboxes, and role addresses from your list is the fastest single thing you can do.

How it works: what happens when you hit verify

1. Type an address or drop a CSV. Paste a single email into the box or upload a CSV, TXT or TSV file. We detect email addresses in any column automatically. Free for up to 10 addresses at a time right now.
2. We run six checks instantly. Syntax, disposable domain, role-based address, free-mail provider, catch-all heuristic, and did-you-mean, all client-side in your browser. More checks (MX, SMTP) are coming in the API release.
3. Get a verdict and act on it. Each address returns valid, risky, or invalid with a per-signal breakdown. Download the results as a CSV and suppress or segment accordingly before your next send.

What we check: what runs today, and what's still on the way

Live now

• Syntax (RFC 5322): catches malformed addresses, illegal characters, double-dots and missing TLDs.
• Disposable domain: compares the domain against known temporary inbox providers such as Mailinator, GuerrillaMail and 10MinuteMail.
• Role-based address: flags shared inboxes (info@, support@, admin@, noreply@) that generate disproportionate complaint rates.
• Free-mail provider: identifies Gmail, Yahoo, Outlook, iCloud and similar so you can score B2B vs B2C contacts.
• Catch-all heuristic: detects domains likely configured to accept all mail and flags the result as risky.
• Did-you-mean: spots common typos like gmial.com, yaho.com and hotnail.com, and suggests the correct domain.

Coming with the API

• MX record lookup: confirms the domain has an active mail exchanger.
• SMTP handshake: opens a live conversation with the receiving server to confirm the specific mailbox exists.

Who it's for

• Email marketers: clean your list before every major send and keep your bounce rate under 2%.
• Growth & product teams: catch bad addresses before they enter your database.
• Freelancers & agencies: verify client lists without sharing them anywhere, since everything runs in your browser.
• Anyone with a lead form: spot the typos that cost you real money.

Pricing

Free forever ($0). You don't need to sign up, hand over a card, or worry about it ever going away. Includes single-address verification, bulk CSV upload (up to 10 addresses), downloadable results CSV, all six checks, and 100% browser-based privacy.

Coming soon (pricing to be announced). Unlimited bulk verification, a REST API with JSON responses, MX lookup, SMTP handshake, per-address confidence scores and webhooks. Real numbers will be published before any of this goes live.

Why we built this

We kept bouncing emails from leads that looked perfectly valid. We'd run a campaign, get a 12% bounce rate, and have no idea which addresses were the culprit. Most verification tools either cost money immediately, required an account, or gave a single pass/fail verdict with no explanation. We wanted to know why an address was risky, not just that it was.

So we built EmailVerifyerAPI, starting with the simplest useful thing: a free, no-account, browser-based checker that tells you exactly which signals it ran and what each one found. We're a small team in Montréal, QC, Canada, still early - no enterprise contracts or funding announcement to point to, just a tool that works and a roadmap we're building in public. You can email us directly and a human replies.

Key terms

Disposable email address

A temporary inbox from providers such as Mailinator or GuerrillaMail, created to receive mail briefly and then discarded.

Role-based address

A shared mailbox tied to a function rather than a person, such as info@, support@ or admin@, which tends to generate higher spam-complaint rates.

Catch-all domain

A domain configured to accept mail for any address before the @ symbol, so a server cannot confirm whether a specific mailbox exists.

Hard bounce

A permanent delivery failure, usually because the mailbox or domain does not exist. High hard-bounce rates damage sender reputation.

Spam-complaint rate

The share of delivered messages that recipients mark as spam. Google and Yahoo's 2024 bulk-sender rules require keeping this below 0.3%, ideally under 0.1%.

SMTP handshake

A live connection to a receiving mail server to confirm a specific mailbox exists, the most authoritative verification step, planned for the EmailVerifyerAPI API.

Frequently asked questions

What is email verification?

Email verification is the process of checking whether an email address is valid, correctly formatted, and likely to receive mail. It includes syntax validation (RFC 5322), checking whether the domain has a mail server (MX record), detecting disposable or role-based addresses, and, in full verifiers, an SMTP handshake to confirm the specific mailbox exists.

What does EmailVerifyerAPI check?

EmailVerifyerAPI runs six checks entirely in your browser: syntax validation (RFC 5322), disposable domain detection, role-based address detection, free-mail provider detection, a catch-all domain heuristic, and did-you-mean typo correction. MX record lookup and SMTP handshake verification are planned for the upcoming API.

Does EmailVerifyerAPI store the email addresses I verify?

No. All checks run client-side in your browser. The addresses you type or upload never leave your device, are never sent to any server, and are not logged. There is no account and no database.

Is EmailVerifyerAPI free?

Yes - single-address verification and bulk CSV upload (up to 10 addresses at a time) are completely free, no signup or card required. A paid tier for unlimited bulk and a REST API is planned but has not been priced or released yet.

What bounce rate is too high, and what do Google and Yahoo require?

Many email service providers treat a hard-bounce rate above roughly 2% as a warning sign. Separately, Google and Yahoo's bulk-sender requirements, effective February 2024 for senders of 5,000+ messages per day, require keeping the spam-complaint rate below 0.3%, ideally below 0.1%, alongside SPF, DKIM, DMARC and one-click unsubscribe.

Why does email list hygiene matter?

Marketing email lists decay by roughly 22% per year as people change jobs and abandon inboxes (HubSpot). Sending to invalid addresses raises your bounce rate and can increase spam complaints, both of which damage sender reputation and deliverability.

Who built EmailVerifyerAPI?

A small team based in Montréal, Québec, Canada - see "Why we built this" above for the full story. The free browser tool is our first public release. Email the team directly at [email protected].

Sources & methodology

Every factual claim on this page is attributed. List decay figures are from HubSpot (2024). Bulk-sender spam-complaint thresholds are from Google and Yahoo's sender requirements published in February 2024. Invalid-address rates for unverified lists are industry estimates (HubSpot, Campaign Monitor). EmailVerifyerAPI does not publish invented review counts, ratings, or certifications.

Contact

Every message reaches an actual person here, not a ticket queue - expect a reply within one to two business days. Email us at [email protected]. Available in English and French.