Email Verifier — Bulk SMTP & MX Validation, Catch-all

Email Verifier for Bulk Email Validation

Email Verifier checks the addresses you provide with syntax, disposable and role-account lists, DNS MX records, and an SMTP probe, and returns a status, score, and verification fields. Outbound port 25 is normally closed on Apify, so most runs rely on the non-SMTP checks (see Limits).

• Verify addresses in bulk without sending a message or issuing a DATA command
• Clean B2B lead lists and outreach databases with status, confidence scores, and MX details
• Validate signup addresses and flag disposable or generic role accounts
• Catch-all detection when an SMTP probe completes

What you get

Each address goes through syntax, disposable-domain, role-account, DNS MX, optional SMTP, and catch-all checks.

Field	Type	Description
email	string	Normalized, lowercased address; not null or empty in a returned record
status	string	deliverable, undeliverable, risky, or unknown; not null
score	integer	Confidence from 0 to 100; not null
syntax_valid	boolean	Passes syntax validation; not null
is_disposable	boolean	Domain is on the built-in temporary-mail hotlist; not null
is_role	boolean	Generic role local part such as info, support, or admin; not null
mx_found	boolean	Result of the DNS MX check; not null
mx_host	string	Highest-priority MX hostname; null when no MX is found
smtp_code	integer	Raw SMTP response; null if SMTP is unreachable, skipped, or does not complete
smtp_message	string	SMTP response text, or a reason such as the port-25-blocked note; null when SMTP is skipped
is_catch_all	boolean	Domain accepts arbitrary local parts; null when SMTP is skipped, unreachable, or catch-all status cannot be determined
checked_at	ISO 8601 string	UTC timestamp for the check; not null

A field is null when the source does not provide the value.

Disposable domains are checked against a built-in hotlist of known temporary-mail providers. It is deliberately not exhaustive, so a disposable domain missing from it is not flagged. Generic role local parts such as info, support and admin are flagged in is_role.

If DNS returns no MX record, the Actor checks for an A-record fallback. A DNS timeout or other DNS failure counts as no MX (undeliverable, score 0).

SMTP connects to the highest-priority MX host on port 25 and uses HELO, MAIL FROM, and RCPT TO. It reads the RCPT TO response and closes the connection without delivering a message. After a 250 response, a random non-existent address is checked to identify catch-all domains.

Before the first address, the Actor tests whether port 25 is reachable. If it is closed, every address skips SMTP. If a run starts with port 25 open but 5 probes in a row are unreachable and none has connected, the Actor stops probing for the rest of the run.

Sample output

A record from a real run on Apify for a public throwaway address on the disposable mailinator.com domain, where port 25 was blocked: smtp_code and is_catch_all are null, and smtp_message carries the blocked-port note. Score 5 is what a disposable domain gets when an MX is found and the SMTP probe is unreachable. A role address on a non-disposable domain in the same situation returns unknown, score 60 instead.

{
  "email": "user@mailinator.com",
  "syntax_valid": true,
  "is_disposable": true,
  "is_role": false,
  "mx_found": true,
  "mx_host": "mail.mailinator.com",
  "smtp_code": null,
  "smtp_message": "connection_failed: outbound port 25 is blocked in this environment (detected once per run; SMTP probe skipped, MX/DNS result only)",
  "is_catch_all": null,
  "status": "undeliverable",
  "score": 5,
  "checked_at": "2026-10-30T01:29:09Z"
}

Pricing

The Actor uses pay-per-event pricing: a start charge per run (one event per GB of run memory, minimum one) and a charge per dataset item.

You pay only for the events listed below. This Actor does not use the Pay per event + usage option, so the platform usage of your runs (compute, proxy traffic and storage) is not billed to you separately.

Plan	Actor Start	Dataset item
Free	$0.00005 per event on Free plan	$0.0009 per event on Free plan

The email-verification event name has no price of its own in the price list; each returned record is billed as the priced dataset item in the table above.

For one Actor Start event:

1,000 dataset events: $0.00005 + (1,000 × $0.0009) = $0.90005 on the Free plan

10,000 dataset events: $0.00005 + (10,000 × $0.0009) = $9.00005 on the Free plan

The Apify Free plan includes $5 of monthly platform usage credit; the $5 credit covers 5,555 priced dataset events after one Free-plan Actor Start event.

How to use

1. Prepare an emails list of plain strings or objects with an email key.
2. Choose concurrency, SMTP timeout, and SMTP mode. Use skipSmtp: true to skip the SMTP step and avoid waiting on a closed port.
3. Run the Actor with an input such as the one below (start it with Start in Apify Console, or through the Apify API; the Console prefill already holds three runnable addresses):

{
  "emails": [
    "user@mailinator.com"
  ],
  "concurrency": 10,
  "smtpTimeoutSecs": 10,
  "skipSmtp": false
}

4. Inspect returned records for status, score, flags, and MX/SMTP values.
5. Filter records according to your workflow, reviewing risky, disposable, and role-account results separately.
6. Schedule the run through Apify Schedules as a starting point, such as weekly for lead-list verification.

Export the dataset as JSON or CSV, or read it through the Apify dataset API.

Input parameters

Parameter	What it does	Default
emails	Required plain strings or objects with an email key; maximum 10,000 entries per run	Required
concurrency	Emails verified in parallel; range 1–50, with 5–20 recommended	10
smtpTimeoutSecs	Timeout for each SMTP attempt; range 3–30 seconds	10
skipSmtp	Skips SMTP and uses MX-only mode	false
disableUsageStats	Set to true to turn off the run summary described in Usage statistics.	false

Limits and edge cases

Output rows reach the dataset as each address finishes, before its charge is attempted. If a run is aborted, times out, or fails after rows are pushed, those rows remain and addresses not yet pushed have no rows.

The Actor writes an OUTPUT record with emails_verified and a reason to the run's default key-value store when it:

• fails on unusable input;
• stops early on the cost-efficiency check;
• finishes with port 25 blocked.

A run you abort yourself, or one that times out, does not write it.

Condition	What you see	What to do
More than 10,000 entries	The run uses the first 10,000	Split the list
emails is empty, or has no usable strings or email values	The run fails with an input-needed message and emails_verified: 0	Add addresses as strings or objects with an email key
Syntax is invalid	undeliverable, score 0; no network round-trip	Correct the address
No MX record, no A-record fallback, or a DNS timeout	undeliverable, score 0	Check the domain; re-run if DNS was flaky
Port 25 is blocked or SMTP times out (the usual case on Apify)	smtp_code is null. Known providers (Gmail, Outlook, Yahoo, iCloud, Proton, AOL, Zoho and similar) return deliverable, score 80, a domain-name heuristic with no mailbox check. Domains on the disposable hotlist return undeliverable, score 5. Other domains return unknown, score 60	Treat 80 and 60 as unconfirmed
skipSmtp is true	No SMTP probe; the same MX-only rules apply	Use it to avoid the port-25 preflight
SMTP returns 250 and the random address is rejected	deliverable, score 100	Highest-confidence result
SMTP returns 250 but the catch-all check does not complete	deliverable, score 100, is_catch_all null	Catch-all status is unknown; review separately
SMTP returns 250 for the random address too	risky, is_catch_all: true, score 40	Review the mailbox separately
SMTP returns a 4xx response	risky, score 35	Re-verify later or review it
SMTP returns a 5xx response	undeliverable, score 0	Remove or correct the address
SMTP returns any other code	unknown, score 50	Re-verify or review it
A server accepts an address with 250	Acceptance does not guarantee that a later message will not bounce silently	Treat the score as a verification signal
High concurrency is used against one domain	Mail servers may return more 4xx responses from rate-limiting	Reduce concurrency; the default of 10 is conservative
The cost-efficiency stop occurs before the first row	The run fails with emails_verified: 0	Run again with a smaller list
The cost-efficiency stop occurs after rows are written	A partial run reports emails_verified and emails_not_processed	Run the remaining addresses later with a smaller list

To see whether SMTP worked, check smtp_code: null means the SMTP step did not complete.

FAQ

How much does it cost to scrape email addresses?

This Actor verifies addresses rather than finding them. Actor Start costs $0.00005 per event on the Free plan and each dataset item costs $0.0009 per event on the Free plan; see Pricing for the worked calculation.

Why can a result be unknown or risky?

unknown generally means an MX result was found but SMTP could not be reached (score 60), or an unexpected SMTP code came back (score 50). risky means the domain is catch-all or the SMTP server returned a temporary 4xx response.

What happens if the run returns no results or does not work?

An empty emails list or a list without usable entries fails with an input-needed message. If SMTP is unavailable, the Actor still returns records from the other checks.

Is it legal to verify email addresses using public data?

The Actor works with the addresses you provide, DNS records and mail-server responses. Whether verifying them is lawful depends on your use case and local law, so check that before use.

Related actors

• Bulk Email Verifier — validates emails with MX, disposable, and role checks.
• Email Finder — finds a work email from a name and domain before verification.
• Email Finder Bulk — finds emails from lists of domains or people before verification.

Usage statistics

This Actor creates a small, content-free summary at the end of each run, used only to monitor reliability and improve this Actor. No input values, credentials or scraped data are sent.

A copy of the exact record for your run is saved as USAGE_STATS in your own Apify key-value store.

To opt out, set disableUsageStats to true in the input. Nothing is sent then.

Full list of collected fields