Lead File Import Checker

Check a lead file before it goes into your CRM or sequencer. Give it rows, a link to a CSV file, or an Apify dataset, and every row comes back with the problems an import would carry: a broken or disposable email address, a duplicate, a role inbox, a free mail address on a B2B list, an email domain that cannot receive mail, a dead or parked company website, a company name that does not match the website, or a missing required field. Each row gets one verdict, import, review, or reject, so you can filter the file and load only what is clean.

This actor does not verify mailboxes. It never connects to a mail server and never sends anything, so it cannot tell whether a specific inbox exists. It checks the address, the lists, the domain's DNS, and the company homepage. To verify mailboxes, run the clean rows through the mailbox verifier you already use, on your own account.

Features

• One verdict per row. reject for rows that should stay out, review for rows a person should look at, import for rows with no issue. The issues column lists every reason.
• Duplicates, the way inboxes see them. Jane@Stripe.com and jane+news@stripe.com are one person; so are j.doe@gmail.com and jdoe@gmail.com. Rows with no email are grouped on domain plus first and last name. The first row in a group is kept and the rest point back to it.
• Address checks. Syntax, free mail (119 consumer domains such as gmail.com and outlook.com), role inboxes (98 names such as info, sales, and support), and disposable domains (9,963 from the public CC0 list).
• Domain checks. DNS A, AAAA, and MX for the email's domain, so a typo domain or a domain with no mail server is caught before a bounce.
• Website checks. One homepage read per company domain, at most 64 KB: live or not, parked or for sale, and whether the company name in your row appears in the homepage title or the names the site gives itself (og:site_name, application-name, og:title). Pages are decoded in their own character set.
• Any file shape. Common header names are found on their own (Email, Work Email, Website, Company Name, First Name), or name your columns in column_map. Comma, semicolon, tab, and pipe separators are detected.
• Your original row comes back. input_row_json carries it, and row_index keeps the file order.

Input

Field	Type	Default	What it does
rows	array of objects		Your rows as JSON. One of rows, csv_url, or dataset_id
csv_url	string		A public link to a CSV file with a header row, up to 50 MB
dataset_id	string		An Apify dataset from one of your runs
column_map	object		Which column holds email, domain, company, first_name, last_name, and date
required_fields	array	["email"]	Fields a row must have, or it is rejected
checks	array	all	Any of syntax, duplicates, free_mail, role, disposable, dns, site, company_match, missing_fields, stale
check_websites	string, true or false	true	Read company homepages for the site and company name checks
stale_days	string		With a date column: rows older than this many days get stale
max_rows	string	5000	Check at most this many rows, up to 50,000
max_charge_usd	string		Stop before a charge that would pass this amount

Output

One row per input row, in file order. Every row has the same columns.

Field	Type	Meaning
row_index	integer	Position of the row in your file, counting from 1 after blank rows are skipped. Use it to join the results back.
import_verdict	string	import: no issue found. review: an issue to look at (free mail, role address, parked or unreachable site, company name mismatch, stale, email and domain columns disagree, DNS error). reject: an issue that should keep the row out (bad syntax, disposable address, duplicate, email domain does not exist or has no mail server, missing required field).
issues	array	Every issue found, as codes: invalid_email_syntax, free_mail_address, role_address, disposable_address, duplicate, email_domain_not_found, email_domain_no_mx, domain_not_found, dns_error, email_domain_differs_from_domain, site_unreachable, site_parked, company_name_mismatch, missing_required_field, stale.
input_email	string	The email cell from your file, unchanged except for trimming.
input_domain	string	The domain or website cell from your file.
input_company	string	The company cell from your file.
input_first_name	string	The first name cell from your file.
input_last_name	string	The last name cell from your file.
normalized_email	string	The address lowercased and trimmed, when its syntax is valid.
normalized_domain	string	The registrable company domain: from the domain column when given, otherwise from a work email address (a free mail domain such as gmail.com is kept only when nothing else is known).
email_syntax_valid	boolean	true when the address is well formed, false when it is not, empty when the row has no email.
is_free_mail	boolean	true for a consumer mailbox domain such as gmail.com or outlook.com.
is_role_address	boolean	true when the part before @ names a function or a shared inbox (one of 98 role names, such as info, sales, support, and hr), not a person.
is_disposable	boolean	true when the domain is on the public disposable email list (9,963 domains, CC0, read 2026-10-27).
duplicate_group	string	The key rows are grouped on: email:<address without +tag, and without dots for Gmail>, or person:
is_duplicate	boolean	true for every row after the first one in its group. The first row is false.
duplicate_of_row_index	integer	The row index of the first row in the group, on a duplicate.
domain_resolves	boolean	The email address's domain (or the domain column when the row has no email) has a DNS A, AAAA, or MX record.
has_mx	boolean	The same domain publishes at least one MX record, so it can receive mail. This is not a mailbox check.
mx_host	string	The highest priority MX host.
site_status	integer	HTTP status of the company domain's homepage, after redirects. 401, 403, and 429 mean the site refused the check and are not counted as unreachable. Empty when the site did not answer.
site_final_url	string	The homepage address after redirects.
site_title	string	The homepage title, up to 300 characters. Empty behind a bot wall.
is_parked	boolean	true when the homepage is a for sale or parking page.
company_name_match	string	match or mismatch: the company cell compared with the homepage title and the names the site gives itself (og:site_name, application-name, og:title). unknown: no company cell, no readable homepage, or a page with no Latin letters. A domain that only contains the name does not count as a match.
missing_fields	array	Required fields that are empty in this row (required_fields, default email).
stale_flag	boolean	true when the date column is older than stale_days. Empty unless both are set.
input_row_json	string	Your original row as JSON, up to 5,000 characters, so the output can replace the file.
row_status	string	ok for a checked row. error only on the single row a refused input writes.
error_reason	string	dns_error with the resolver error, or input_invalid with the reason on a refused input.
billable_events_json	string	What this row was billed as, for example {"row-checked":1}. {} means free.
checked_at	string	When the row was written, UTC.

Example row:

{
  "row_index": 1,
  "import_verdict": "import",
  "issues": [],
  "input_email": "Jane@Stripe.com",
  "input_domain": "stripe.com",
  "input_company": "Stripe",
  "input_first_name": "Jane",
  "input_last_name": "Doe",
  "normalized_email": "jane@stripe.com",
  "normalized_domain": "stripe.com",
  "email_syntax_valid": true,
  "is_free_mail": false,
  "is_role_address": false,
  "is_disposable": false,
  "duplicate_group": "email:jane@stripe.com",
  "is_duplicate": false,
  "duplicate_of_row_index": null,
  "domain_resolves": true,
  "has_mx": true,
  "mx_host": "aspmx.l.google.com",
  "site_status": 200,
  "site_final_url": "https://stripe.com/",
  "site_title": "Stripe | Financial Infrastructure to Grow Your Revenue",
  "is_parked": false,
  "company_name_match": "match",
  "missing_fields": [],
  "stale_flag": null,
  "input_row_json": "{\"Email\":\"Jane@Stripe.com\",\"Company\":\"Stripe\"}",
  "row_status": "ok",
  "error_reason": null,
  "billable_events_json": "{\"row-checked\":1}",
  "checked_at": "2026-10-28T14:00:00.000Z"
}

The run also writes a RUN_SUMMARY record with the columns it used, counts per verdict and per issue, blank rows skipped, and rows over max_rows.

What each verdict means

Verdict	Issues that set it
reject	invalid_email_syntax, disposable_address, duplicate, email_domain_not_found, email_domain_no_mx, missing_required_field
review	free_mail_address, role_address, site_parked, site_unreachable, company_name_mismatch, stale, email_domain_differs_from_domain, domain_not_found, dns_error
import	none

Pricing

Pay per event. You pay for checked rows and the run start.

Event	Free plan	Bronze	Silver	Gold
row-checked, one row of your file checked	$0.002	$0.0019	$0.0018	$0.0017
apify-actor-start, once per run (one per GB of memory; the default 512 MB is one)	$0.001	$0.001	$0.001	$0.001

Per 1,000 rows: $2.00 on the free plan, $1.70 on Gold. Every check is included; turning checks off does not change the price.

Free: blank rows, rows over max_rows, and the one row a refused input writes. A refused input charges only the run start.

Free plan cap: 1.50 USD of evaluation a month, about 750 checked rows. Any paid Apify plan removes the cap, and it resets on the 1st. The run stops before a charge that passes your maximum charge per run in Apify or your max_charge_usd.

Mamba Labs pays the platform costs of your run. No key is needed and no paid lookup service is called.

Usage examples

Apify Console or API. Paste rows, or give a CSV link:

{
  "csv_url": "https://docs.google.com/spreadsheets/d/e/YOUR_SHEET/pub?output=csv",
  "column_map": { "email": "Work Email", "company": "Account" },
  "required_fields": ["email", "company"]
}

Read the rows with GET https://api.apify.com/v2/datasets/{datasetId}/items?format=csv and filter on import_verdict.

After another actor. Pass the defaultDatasetId of a lead list run as dataset_id, and check the list before it reaches your sequencer.

Clay. Export the table to CSV or publish it as a link, run the checker on csv_url, and import the result back on row_index.

MCP. The Mamba Labs MCP server @mambalabsdev/mcp-lead-file-import-checker exposes the tool check_lead_file to Claude and other MCP clients.

Error handling

Case	What you get
No source, two sources, an unreadable CSV link, a web page instead of a CSV, an empty file, or no email or domain column	One free row, row_status error, error_reason starting input_invalid:, and the run ends successfully. Only the run start is charged
A blank row	Skipped and not charged; counted in RUN_SUMMARY
A DNS lookup fails (not a "does not exist" answer)	dns_error in issues, verdict review, the reason in error_reason
A homepage that refuses the check (HTTP 401, 403, or 429) or shows a bot wall	Not an issue: site_status shows the code, company_name_match is unknown
The run nears its timeout	It stops starting rows 90 seconds before the timeout and ends successfully; rerun from the next row_index

Limitations

• No mailbox verification, by design. In a test on 2026-10-28, Apify's network did not connect to port 25 on any of 4 mail servers, directly or through the Apify proxy, so an SMTP mailbox check cannot run here. A valid address on a domain with an MX record can still bounce.
• Catch all domains are not detected, for the same reason.
• Free mail is flagged for review, not rejected, because some B2B leads (founders, freelancers) use one.
• The company name match reads the homepage title and the site's own name tags only. A page with no Latin letters reads unknown. A brand that differs from its legal name (a company listed as "Alphabet" on google.com) reads mismatch; check those by hand.
• Files over 50 MB, or over 50,000 rows per run, must be split.
• A date column is read with standard date formats; an unreadable date leaves stale_flag empty.

Mamba Labs actor suite

Actor	Actor ID
Account Hiring Watch	gRAZA5WBi1r6L0gy7
Agent Accessibility Auditor	anxbRv0lKrpQ1pnua
Agent to Brokerage Resolver	ePRRGLxOGyaVHO4dI
AI Tooling Detector	EwkHhmqiuJgRoVEbE
B2B Reddit Conversation Monitor	SoDryzzsjmY3SsiyG
Bluesky Brand Presence Mapper	eLpxzP4IuXznlFVND
Career Change Signal Engine	vX2Yga1a6wGaXaP14
Company Change Event Feed	oX44rS0fkEJ3rXLWe
Company Contact Details Extractor	4mMncKaJykiq94grz
Company Discovery List Builder	jch0HdaZnpbMqlcGS
Company Firmographic Enricher	YlUtLWjfPpqykmB8g
Company Funding Record	OFS4Mt1gyYNtGfUbE
Company Headcount Estimator	aHC4GROnNt6kfZe5r
Company Identity Resolver	lr8fTRAmZCBZmuwwh
Company Social Presence Mapper	4k6CCemkgBDz18m2h
Competitor Price, Stock, and Changelog Monitor	yxdgCbUQ4PYQWwRNU
Contact Classifier	0lGSeYJmniXhGANnO
Contractor License Lookup	WBYK3CPI2kdeq4bP1
Cookie Consent Audit	TrKyOS0KBoGC35nbr
Domain Deliverability Checker	0tVgxI7A6o9jMlxmc
Domain to LinkedIn URL Resolver	3HtnSaqPHOg1Qg5gx
Ecommerce Platform Profiler	5G2NeYjBbQTjaTn9L
Ecommerce Store Discovery	PeHu4sLyFvQHXUUrX
Event Presence Index	WLhMy8fMDgsxdYxv5
Expert Witness Directory	LIpwlgfE3LaQBaXd4
Funding and Press Signal Scanner	FS13X6dhQVgX3XOM6
GitHub Organization Signal Scanner	ahF8RRpv5mzPao5CN
Google Ads Transparency Monitor	1eOwxhBVxzvOXAm4s
Government Contract Award Monitor	zhEtllASykOcx9hJ8
GTM Hiring Signal Scraper	D7O1SA2EqwHGsGr1P
GTM Signals Aggregator	xKdRfnfFNkdMpFuNs
ICP Fit Scorer	W161DT8W4kW55dMFh
Influencer Change Monitor	d2VVgahNL6UmcLkhg
Influencer Finder	tpkedmloIIWtXx6sg
Influencer Lead List Builder	KnmByszcv135yM30G
Influencer Profile Scraper	EqEnklDVMIcB1V499
Influencer Talent Agency Lookup	zCuX4Mgyg6JvXgGzd
Instagram Facebook Brand Presence Mapper	HXh65I0JBjPsunbY8
Integration and Marketplace Presence Mapper	V0guNuvM85Q61f2gj
Job Board Keyword Signal Scanner	4DvqpvhMR74NLcDDY
Job Change Tracker	L8UbEmMJC1XYPSZOb
Job Posting Monitor	QCfICD9kOPiOdj5iI
Legal Entity Resolver	KHFyPCDIx7CyqULYm
Link in Bio Scraper and Newsletter Detector	OorucdheTIgu7RFzK
LinkedIn Company Page Mapper	zOPm6A9JEhUGcIdFW
LinkedIn Post Tracker	oiGLNPuaf5BRaz9K5
Local Business Lead Builder	qMN97aoHhsAS5bznV
Local Rank and Map Pack Tracker	gv0kyHGDIg8XscclB
Lookalike Company Finder	e2O426WBAbLLQL4Z2
Manufacturer and Supplier Finder	Qcsdmd0lUfPzVkonh
Meta Ad Library Monitor	J1GWlSXfSGU3u8Wng
Mobile Phone Waterfall	6OOgPktf7RIa5XCOP
New Company Registrations Feed	g2WfZhWvCtc57g2Jo
New Hire Finder	cKuc38p4nYHNF3IW8
Newsletter Sponsor Tracker	qSwpqxD1TiPZpLQHv
Open Tender and RFP Finder	kPTGz6t6TFoUUyfaO
Outbound Stack Detector	v43UJC8r7qW7cBSTG
Page Finder and Extractor	TpurgcOZbVnknlaiC
Partner and Member Directory Extractor	ZX0XJPPUvnFJxeC1a
People Finder & Email Verifier	LEgloG7tWgQl4o6TD
Person LinkedIn URL Resolver	ssuyPV8LnEsL8qbnb
Person Social Footprint Mapper	jfQXa2zW9FHCJot9K
Personal Email to Company Resolver	AefT5Ye6YNPFQwJBf
Pinterest Brand Presence Mapper	d1HvjZfKhgvWsoEwn
Podcast Guest and Host Finder	o2MGSvgbSLeeXOsIo
Prospect Engine	q9rT6v64nUJdPexOQ
Public Feature Board and Roadmap Monitor	rcHF5gj5r2Vqnry35
Publishing Frequency Tracker	TbLwaUUATdYb6wp4N
Reddit Brand Presence Mapper	pKQZmDaT70SEb54bZ
Reporting Window Finder	uINxR7a1IW8qUTRUX
Sequencer Event Poller	S6s8Rjd61tGdrMRk4
Sequencer Lead Push	0Jv27VeWM5tSZQs9x
Team Page People Extractor	j8a9zX0k4mNbvDbWK
Tech Stack Signal Detector	qyd7nNyqFPelQViBx
TikTok Brand Presence Mapper	fco8FvoJcSafbeyd1
Trustpilot Reputation Enricher	3lIqfCt61j4hqE1xz
VC and Accelerator Portfolio List Builder	chH8hrfuoqqolW06m
WCAG Accessibility Audit	P3jBj3FRghKEhX52z
Website Phrase and Business Model Classifier	CBuZ9k7sRwBeiKiCS
Website Traffic Rank Estimator	GnOFUzlNVIoXgeJjH
Work Email Waterfall	OT6xqTFThC0Rjf7Zj
Workplace Program Detector	Li6pPDhqbdzFz3h7G
X Brand Presence Mapper	oLOgadhHUkNAyDA3w
YouTube Channel Stats Extractor	6hSpD3kd2s2IQ4VSs

MCP servers for the suite are published under the npm scope @mambalabsdev.

Built by Mamba Labs.