What does an email verifier do?

An email verifier confirms that an email address exists and can receive messages: without sending a test email. Tomba's Email Verifier runs 7 comprehensive checks including SMTP verification, MX validation, catch-all detection, and disposable filtering to give you a clear deliverability verdict.

How does Tomba verify emails without sending them?

Tomba connects directly to the email's SMTP server and simulates a delivery handshake. This confirms the mailbox exists without actually sending a message: accurate, instant, and non-intrusive.

What checks does the Email Verifier perform?

Each email goes through 7 checks: format validation, domain and MX record verification, SMTP server connection, mailbox existence test, disposable email detection, block list screening, and catch-all domain analysis. The result is a clear confidence score from 0 to 100.

What is the bounce rate for emails marked Valid?

If an address Tomba returned as valid hard-bounces, the credit comes back under the data-quality guarantee (verifier result deliverable or finder score of 60 or more, sent within 30 days from a domain with SPF, DKIM and DMARC).

Can I verify emails in bulk?

Yes. Upload a CSV to the Bulk Email Verifier and process thousands of addresses at once. Typical speeds are 1,000 emails in under 5 minutes and 20,000+ in a few hours.

How much does email verification cost?

Each verification uses one credit. If verification fails, no credit is consumed. The Free plan has no verification credits: verification comes with the paid plans. Need more? Check our pricing plans for higher limits.

What is the rate limit for the Email Verifier?

Limits are per plan, in requests a second / a minute / a day: Free 1 / 2 / 10, Basic 2 / 40 / 500, Growth 3 / 60 / 1,000, Pro 5 / 100 / 4,000. Pro Plus and Scale have no limit, and Enterprise allows 100,000 requests a day with no per-second limit. Every response carries rate-limit headers; see Rate limits .

Can I use the Email Verifier with n8n, Make, or Zapier?

Yes. Tomba has native apps for n8n , Make , and Zapier , so you can verify an address inside any automated workflow without writing code. Common setups: verify every new signup before it reaches your CRM, clean a list on a schedule, or block invalid addresses at the form. If you would rather build it yourself, use the Email Verifier API , the CLI , or our MCP server for AI agents.

How does catch-all detection work?

A catch-all (accept-all) domain accepts mail sent to any address, so an ordinary SMTP check reports valid even for mailboxes that do not exist. Tomba detects catch-all domains as part of every verification and reports them as their own status rather than a false Valid. Unlike verifiers that stop there and return unknown, Tomba goes further to resolve many catch-all addresses: see the Catch-All Verifier and the Catch-All Finder .

// email verifier

Know if an address will deliver before you hit send

Tomba checks the syntax, the domain, the mail server and the mailbox, flags catch-all, disposable and webmail addresses, and returns a status with a score.

Get free API key API reference

// api console

GET /email-verifier

curl -G https://api.tomba.io/v1/email-verifier \
  --data-urlencode "email=richard@piedpiper.com" \
  -H "X-Tomba-Key: $TOMBA_API_KEY" \
  -H "X-Tomba-Secret: $TOMBA_SECRET_KEY"

const params = new URLSearchParams({
  email: "richard@piedpiper.com"
});
const res = await fetch(`https://api.tomba.io/v1/email-verifier?${params}`, {
  headers: {
    "X-Tomba-Key": process.env.TOMBA_API_KEY,
    "X-Tomba-Secret": process.env.TOMBA_SECRET_KEY
  }
});
const { data } = await res.json();

import os, requests

res = requests.get(
    "https://api.tomba.io/v1/email-verifier",
    params={
        "email": "richard@piedpiper.com",
    },
    headers={
        "X-Tomba-Key": os.environ["TOMBA_API_KEY"],
        "X-Tomba-Secret": os.environ["TOMBA_SECRET_KEY"],
    },
)
data = res.json()["data"]

ExampleExample response from the API reference

email.email: richard@piedpiper.com
email.result: deliverable
email.status: valid
email.score: 99
email.smtp_provider: Google
email.accept_all: false
email.disposable: false
email.webmail: false
email.greylisted: false

// teams at these companies use tomba

// 01 · in the app

Email Verifier in the Tomba app

Paste an address in the web app: the verdict, the score and every check behind it, on the same credits as the API.

app.tomba.io/verify/richard@piedpiper.com

Email Verifier

richard@piedpiper.com

Valid99% Low riskGoogle

This email address can be used safely.

Format validation

Valid syntax Yes
Gibberish No

Domain type

Webmail No
Disposable No

// also in

// 02 · the api

Email Verifier is one HTTPS request

Send the parameters with your key and secret. Every SDK, the CLI and the MCP server make this same call.

GET/email-verifier

emailrequired: The address to verify
enrich_mobilefalse: Also return phone numbers

// cost

Rate limits by plan

1verification credit

Charged when: The status is not disposable or unknown. Phone numbers returned with enrich_mobile cost 5 search credits each, from the search allowance.

Errors, 429 and 451 responses, and the same request again within your usage window cost nothing.

13 official SDKs: C#, Dart, Deno, Elixir, Go, Lua, Node.js, Perl, PHP, Python, R, Ruby, Rust. Libraries in the docs

GET /email-verifier

200 OK· 1 verification credit

{
  "data": {
    "email": {
      "email": "richard@piedpiper.com",
      "result": "deliverable",
      "status": "valid",
      "score": 99,
      "smtp_provider": "Google",
      "mx": {
        "records": [
          "aspmx.l.google.com",
          "alt1.aspmx.l.google.com"
        ]
      },
      "mx_check": true,
      "smtp_server": true,
      "smtp_check": true,
      "accept_all": false,
      "greylisted": false,
      "block": false,
      "gibberish": false,
      "disposable": false,
      "webmail": false,
      "regex": true,
      "whois": {
        "registrar_name": null,
        "referral_url": null,
        "created_date": null
      }
    },
    "sources": [
      {
        "uri": "https://piedpiper.com/blog/engineering",
        "website_url": "piedpiper.com",
        "extracted_on": "2024-06-01T09:14:07+01:00",
        "last_seen_on": "2025-01-10T17:02:44+01:00",
        "still_on_page": true
      }
    ],
    "phone_data": null
  }
}

GET/email-verifier

data.email.resultstring: deliverable, risky or undeliverable; empty for a disposable domain
data.email.statusstring: valid, accept_all, invalid, unknown or disposable (compare case-insensitively: a live check can return Valid)
data.email.scoreinteger: Confidence: 99 for valid, 77 or more for accept_all, 2 for disposable
data.email.smtp_providerstring | null: Mail provider from the MX records, such as Google
data.email.mx.recordsarray | null: The domain's MX hosts
data.email.mx_check, data.email.smtp_checkboolean: The domain has MX records (smtp_check is the same check; status says whether the mailbox exists)
data.email.accept_all, data.email.greylisted, data.email.blockboolean: Catch-all domain, check deferred, check refused by the server
data.email.disposable, data.email.webmail, data.email.gibberish, data.email.regexboolean: Disposable or webmail domain, random-looking address, valid syntax
data.sources[]array: Where the address was found
data.phone_data[]array | null: Phone numbers, when you send enrich_mobile

// 03 · verdicts

What each status means

Every check returns a status and a result. Disposable and unknown answers are free.

valid1 verification credit
The mailbox exists and accepts mail.
Send.
accept_all1 verification credit
The server accepts mail for any address, so this mailbox can’t be confirmed.
Send with care, or verify again later.
unknownFree
The check was inconclusive: the server blocked it or didn’t answer.
Verify again later.
invalid1 verification credit
The mailbox doesn’t exist.
Remove it from your list.
disposableFree
The domain is a disposable email provider.
Treat it as undeliverable.

status	result	Meaning	What to do	Cost
`valid`	deliverable	The mailbox exists and accepts mail.	Send.	1 verification credit
`accept_all`	risky	The server accepts mail for any address, so this mailbox can’t be confirmed.	Send with care, or verify again later.	1 verification credit
`unknown`	risky	The check was inconclusive: the server blocked it or didn’t answer.	Verify again later.	Free
`invalid`	undeliverable	The mailbox doesn’t exist.	Remove it from your list.	1 verification credit
`disposable`	(empty)	The domain is a disposable email provider.	Treat it as undeliverable.	Free

Status values in the docs

// 04 · customers

What customers say

Tomba is my go-to to validate emails. Even though I might have others to do a waterfall process with, Tomba is usually the top choice in it.
Nuno PocoSales Automation Architect, clickworks.io
Great Value for Money! The Data Accuracy rating and insights as to where and when they found the data. The responsiveness of their help team.
Leon W.Sales Directorvia G2

// 05 · capabilities

Every check behind the verdict

One call runs the checks a bounce would otherwise teach you.

Mailbox check
Tomba asks the mail server whether the mailbox exists, without sending an email.
Domain and MX records
Confirms the domain is live and has mail servers that accept messages.
Catch-all detection
Flags servers that accept every address, so their yes isn't read as valid.
Disposable and webmail
Marks throwaway inboxes and free webmail addresses before they reach your list.
Greylisting handled
When a server asks to retry later, the verifier retries instead of returning unknown.
A status and a score
Every address gets a status such as valid, invalid or accept_all, and a score from 0 to 100.

// 06 · use cases

What teams build with Email Verifier

// 07 · questions

Email Verifier: quick answers

Still have questions? Visit the help center

// verify before you send

Check every address before it bounces

Verify one address in the app or the extension, or a whole list in a bulk job. Verification credits come with every paid plan, separate from search credits.

Compare plans Create a free account

Paid plans from $49 a month. Cancel anytime.

Know if an address will deliver before you hit send

Email Verifier in the Tomba app

Email Verifier is one HTTPS request

What each status means

What customers say

Every check behind the verdict

Mailbox check

Domain and MX records

Catch-all detection

Disposable and webmail

Greylisting handled

A status and a score

What teams build with Email Verifier

Email Verifier: quick answers

Check every address before it bounces