Does this verify the email actually exists on the mail server?

No — this tool checks syntax + heuristics only. Actually proving deliverability requires an MX lookup (DNS) and an SMTP RCPT TO handshake against the recipient server, both of which need a backend (browsers can't open TCP sockets). What this catches: 95%+ of typos, bot/abuse signups via disposable providers, malformed paste from spreadsheets, and addresses that exceed RFC length limits — which is most of what bounces real mailings. For deep verification, pair this with a paid provider (NeverBounce, ZeroBounce) on the validated subset.

Why is `user+tag@gmail.com` valid? Isn't `+` a typo?

The `+` is fully legal per RFC 5322 atext — it's "subaddressing" and is supported by Gmail, Fastmail, ProtonMail, iCloud, and most modern providers. `you+toolora@gmail.com` routes to `you@gmail.com` but lets you filter / track which service leaked your address. Other unusual-but-legal characters in the local part include `!#$%&'*/=?^_\`{|}~-` and dots (except leading, trailing, or doubled).

What's a disposable email and why should I detect it?

Disposable / temp-mail providers (mailinator.com, 10minutemail, guerrillamail, yopmail…) hand out throwaway inboxes that expire in minutes or hours. Bots use them to bypass signup walls, claim free trials, and abuse coupon codes. They're real, valid-syntax email addresses — SMTP verification won't catch them. Detecting them at signup typically reduces fake-account rate by 60-80% on consumer sites. The 30+ providers in the built-in list cover the highest-volume offenders we've seen on Toolora's own signup.

Why not just use a regex like the W3C HTML5 spec one?

That regex is intentionally too permissive (the W3C spec says so explicitly — it's "deliberately a willful violation of RFC 5322" to keep ` ` UX simple). It misses: addresses over 254 chars, local parts over 64 chars, domain labels with leading/trailing hyphens, all-numeric TLDs, doubled dots in the local part, and trailing-dot domains. Worse, it can't tell you *why* something failed — you only get a boolean. This validator returns a structured reason list and a typo suggestion, which is what you actually need to surface "Did you mean gmail.com?" in your UI.

Can this catch every typo?

No, the built-in list covers ~50 of the most common domain typos (gmail / yahoo / hotmail / outlook / icloud / qq / 163 / 126 / protonmail variants). Fuzzy Levenshtein matching against the full Alexa top-1k mail providers would catch more but adds 30-50 KB of dictionary and false-positives a real-but-obscure corporate domain as "did you mean gmail?". The current approach is conservative on purpose — when we suggest a correction, it's almost certainly the intended address.

Cleaning a 12k-row signup CSV export before a launch email

You export 12,400 signups from a form tool and the list is full of `name@gmail,com`, trailing spaces, and `test@test`. Paste the whole column, sort the batch table by status, and pull only the green rows. Cutting 600 malformed addresses keeps your bounce rate under 2% so the campaign does not get flagged as spam by the sending provider.

Blocking disposable signups on a free trial

Your free tier gets hammered by `@mailinator.com` and `@guerrillamail.com` throwaways farming trial credits. Paste a day of new signups, filter the disposable rows, and you instantly see the abuse pattern. Most teams find 8-15% of free signups are throwaway domains, and feeding that list to your block rules cuts fake accounts hard.

Catching the typo that ate a customer's password reset

A support ticket says "I never got the reset email." You paste the address from your CRM and the tool flags `gmial.com` with a suggested fix to `gmail.com`. One letter off, weeks of silent failed delivery. Now you correct it in the record and the next reset lands in seconds instead of bouncing into a void.

Sanity-checking a leaked breach list before research

A security researcher drops a 40k-line credential dump and wants only the structurally valid addresses for analysis. Paste it, export the valid CSV, and skip the garbage rows full of `:` separators and hash fragments. Because nothing leaves the tab, the sensitive list never touches a third-party server.

Email Validator — RFC 5321 Syntax, Bulk Paste, Disposable & Typo Detection

Validate emails — RFC 5321 syntax + bulk paste + disposable detection + MX hint.

Runs locally
Category Text
Best for Removing repetitive cleanup work from everyday writing and operations.

Email address

Type or paste an email above.

What this tool does

Free in-browser email validator. Paste a single address or a list of thousands — every email is checked against RFC 5321 (local part ≤ 64 chars, full address ≤ 254 chars, LDH domain labels, alphabetic TLD) plus a curated list of 30+ disposable / temp-mail providers (mailinator, 10minutemail, guerrillamail, yopmail, tempmail…). Common typos like `gmial.com` → `gmail.com`, `yhoo.com` → `yahoo.com`, and `hotmial.com` → `hotmail.com` get an auto-suggestion. The batch table shows status + reason per row and exports the valid list as CSV. Everything runs in the tab — paste leaked lists or signup CSVs without anything touching a server.

Tool details

Input: Text; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Download; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: No account required; Open the page and use it; whether results survive refresh depends on the tool.
Performance budget: Initial JS <= 22 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Text · Developer; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How Email Validator fits into your work

Use it to clean, compare, reshape, or extract plain text before it goes into a document, CMS, spreadsheet, or prompt.

Text jobs

Removing repetitive cleanup work from everyday writing and operations.
Making text easier to compare, paste, publish, or feed into another tool.
Working with content locally when the text is private or unfinished.

Text checks

Scan for unintended whitespace, duplicate lines, and lost punctuation.
For long text, test the first few lines before applying the whole change.
Copy the final output only after checking the preview.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Cleaning a 12k-row signup CSV export before a launch email
You export 12,400 signups from a form tool and the list is full of `name@gmail,com`, trailing spaces, and `test@test`. Paste the whole column, sort the batch table by status, and pull only the green rows. Cutting 600 malformed addresses keeps your bounce rate under 2% so the campaign does not get flagged as spam by the sending provider.
Blocking disposable signups on a free trial
Your free tier gets hammered by `@mailinator.com` and `@guerrillamail.com` throwaways farming trial credits. Paste a day of new signups, filter the disposable rows, and you instantly see the abuse pattern. Most teams find 8-15% of free signups are throwaway domains, and feeding that list to your block rules cuts fake accounts hard.
Catching the typo that ate a customer's password reset
A support ticket says "I never got the reset email." You paste the address from your CRM and the tool flags `gmial.com` with a suggested fix to `gmail.com`. One letter off, weeks of silent failed delivery. Now you correct it in the record and the next reset lands in seconds instead of bouncing into a void.
Sanity-checking a leaked breach list before research
A security researcher drops a 40k-line credential dump and wants only the structurally valid addresses for analysis. Paste it, export the valid CSV, and skip the garbage rows full of `:` separators and hash fragments. Because nothing leaves the tab, the sensitive list never touches a third-party server.

Common pitfalls

Trusting "valid syntax" as "real mailbox" — `ceo@yourcompany.com` can pass every check and still bounce; always run an MX/SMTP step on the validated subset before a big send.
Treating `+` or dots as errors — `you+toolora@gmail.com` and `first.last@gmail.com` are fully legal; stripping them loses real, deliverable addresses.
Pasting an Excel column with hidden trailing spaces or commas (`a@b.com,`) and then blaming the tool; trim the source first or the row flags as malformed.

Privacy

Every email you paste is validated entirely in your browser tab using JavaScript — no address is ever uploaded, logged, or sent to any server, and nothing is written to a URL (the input is never put into shareable links). Closing the tab clears everything. That is why pasting leaked lists, signup CSVs, or internal rosters here is safe.

FAQ

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Email Validator — RFC 5321 Syntax, Bulk Paste, Disposable & Typo Detection

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How Email Validator fits into your work

Text jobs

Text checks

Good next steps

Real-world use cases

Cleaning a 12k-row signup CSV export before a launch email

Blocking disposable signups on a free trial

Catching the typo that ate a customer's password reset

Sanity-checking a leaked breach list before research

Common pitfalls

Privacy

FAQ

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