Lead Validation: Checking Email, Phone and Company Data Before Outreach

Lead validation means checking each field of a lead record with the test that fits it before anyone acts on it. Verify the email over SMTP. Parse the phone number and, where it matters, look up its line type. Confirm that the company domain exists and accepts mail. Remove duplicates. Then score the whole record and route it: ready, needs review, or reject. No single check proves a lead is good. Together they catch most of what makes outreach fail.

This guide goes field by field, states what each check can and cannot prove, and ends with a scoring rule and a worked example.

Start by normalising and deduplicating

Validate each person once. Before any check:

• Lowercase and trim email addresses.
• Convert phone numbers to E.164 format (+14155550123), so the same number written three ways becomes one.
• Strip https://, www. and paths from website fields, leaving the bare domain.
• Remove exact duplicates, then look for the same person under two addresses.

Field 1: the email address

This is the field most outreach depends on, and the one you can check most rigorously.

A proper email verification runs these steps in order, as our post on syntax, MX and SMTP checks explains:

1. Syntax: is it a well-formed address?
2. Domain: does the domain exist, and does it publish MX records?
3. Disposable and role detection: is it a throwaway domain or a shared inbox like info@?
4. Mailbox: does the receiving server accept this recipient? Answered over SMTP, without sending a message.
5. Catch-all detection: does the server also accept a made-up recipient? If so, its "yes" proves nothing.

Result	What it means	What to do
Valid	The receiving server accepted this mailbox and rejected a made-up one	Ready for email
Risky: catch-all	The domain accepts every address, so this one cannot be confirmed	Review. Send in a capped segment
Risky: role address	A shared inbox such as sales@	Depends on use case
Risky: unverifiable	The server hid the mailbox status or never answered	Review or re-check later
Invalid	The server rejected the mailbox, the domain cannot receive mail, or the domain is disposable	Do not email

The ceiling: on a catch-all domain, no SMTP check can tell a real mailbox from a made-up one. In our Email List Health Report 2026, 27.5% of 54,463 domains accepted a made-up address. Expect a real share of B2B leads to come back risky however good the tool is. The catch-all decision framework shows how to decide how many to send.

Field 2: the phone number

Phone validation has two levels, and they answer different questions.

Level 1: is it a correctly formed number?

Google's open-source libphonenumber is the reference library. Its isValidNumber function performs "full validation of a phone number for a region using length and prefix information". That catches wrong lengths, impossible area codes and numbers missing their country code. It is offline and instant.

It cannot tell you whether the number is assigned to anyone, or to whom. Our guide on how to check if a phone number is valid explains the four levels of checking in detail.

Level 2: what kind of line is it?

A live carrier lookup queries telecom data and returns the line type (mobile, landline or VoIP) and the current carrier. That matters because:

• texts only reach numbers that can receive SMS;
• in the US, calling and texting rules differ for mobile numbers;
• a VoIP number on a "direct dial" field may be a switchboard or a virtual line.

The ceiling: in service is not the same as reachable

A lookup tells you how the number is set up. It does not tell you that the person on your list still has it. Numbers are disconnected and reassigned. In the US, the FCC runs the Reassigned Numbers Database, which "is designed to prevent a consumer from getting unwanted calls intended for someone who previously held their phone number". If you call or text US consumers at scale, check that database alongside your line-type results.

SimpleVerifier's phone checks report format, country and line type. They never claim that a number is in service or that a particular person answers it.

Field 3: the company and its domain

A lead whose company does not exist is not a lead. Check three things.

1. The domain resolves and receives mail. Run an MX lookup. A company domain with no mail servers cannot be the domain in a working business address.
2. The email domain matches the company. jane@acme.com for a lead at Acme is consistent. jane@acme-consulting.net for the same lead is worth a second look. Note that large companies sometimes use a mail domain different from their website domain, as our research on finding a CEO's email found.
3. The address is a business address. A free-mail address (gmail.com, outlook.com) on a B2B lead is a review flag, not a rejection. Disposable domains are a rejection. The disposable email checker checks a domain against our list of 8,740.

Our guide to telling a business email from a personal one covers the edge cases.

Field 4: the name

Name checks are crude, but they catch the obvious fakes, especially on inbound forms.

Flag records where:

• the first or last name is a placeholder: test, asdf, xxx, a single letter or keyboard runs;
• the name field contains an email address or a URL;
• the name and the email clearly disagree, for example John Smith with maria.garcia@company.com. This is common on shared forms and data merges;
• every field is in capitals or none of them are, on a source where that is unusual.

None of these proves a lead is fake. They route the record to review instead of straight into a sequence.

Scoring the whole record

Combine the field results into a routing decision. A simple, transparent rule works better than an opaque score.

Condition	Route
Email invalid and no valid phone	Reject
Email disposable, or name is a placeholder	Reject
Duplicate of an existing record	Merge, keep the most complete version
Email valid, company domain consistent	Ready for email
Email valid, phone mobile and correctly formed	Ready for email, call and text, subject to the rules where the person is
Email risky (catch-all or unverifiable)	Needs review, or a capped email segment
Email invalid, phone valid	Ready for calling only; flag the email for re-sourcing
Free-mail address on a B2B lead	Needs review
Email and company domain disagree	Needs review

The important design choice is that one failed field does not delete a lead. A record with an invalid email and a good mobile number is still a phone lead. A record with a valid email and a landline is still an email lead.

Worked example: 2,000 leads from mixed sources

A sales team pulls 2,000 leads from a webinar registration list and a data-provider export. The figures are illustrative.

After normalising: 1,930 unique people (70 duplicates merged).

Field results:

Check	Pass	Flag	Fail
Email	1,410 valid	340 risky (catch-all, role, unverifiable)	180 invalid, including 12 disposable
Phone present	1,160		770 missing
Phone format (of 1,160)	1,090 valid		70 invalid
Phone line type (of 1,090)	610 mobile, 380 landline	100 VoIP
Company domain	1,700 consistent	230 free-mail or mismatched
Name	1,905 plausible		25 placeholders

Routing:

Bucket	Count	Rule applied
Rejected	110	12 disposable emails, 73 invalid emails with no usable phone, 25 placeholder names
Ready for email	1,330	Valid email, consistent domain, plausible name
Ready for calling only	95	Invalid email, but a correctly formed phone number
Needs review	395	340 risky emails, plus 55 valid emails on a free-mail or mismatched domain

Without validation, the 180 invalid addresses would have gone into a sequence. That is 9.3% of the list, well over the 5% bounce line at which Amazon SES places an account under review and above which Instantly pauses campaigns by default. With validation, 95 of those people are still reachable by phone.

Common mistakes

Mistake	What goes wrong
Treating "valid format" as "reachable" for phone numbers	A well-formed number can be disconnected or reassigned
Deleting every lead with a risky email	Catch-all domains hold many real people. Review them instead
Validating before deduplicating	You pay for, and review, the same person twice
Rejecting all free-mail addresses on B2B leads	You lose founders and small-business owners who use them
Letting a single failed field delete the record	A reachable phone lead or email lead is thrown away
Validating once at entry and never again	Data decays. A lead captured last quarter needs re-checking before use
Mixing validation with enrichment in one step	You pay to enrich records that validation would have rejected

Validate at entry, then again before use

Lead data decays from the moment it is captured. Validate twice:

1. At entry, in real time on forms, or in bulk on imports.
2. Before use, if more than a few weeks have passed.

For automated flows, the SimpleVerifier API checks both email addresses and phone numbers, and the Zapier and webhook guide shows how to verify each new lead as it arrives.

Tools and prices

Need	SimpleVerifier plan
Clean an email list occasionally	Pay-as-you-go: $9 for 2,500 or $19 for 10,000 verifications, credits never expire
Unlimited email verification, email finder, phone format and line-type checks, API	Pro, $29.99 a month
All of Pro, plus 5,000 live carrier lookups a month with real line type (including US numbers) and carrier name	Email + Phone, $49.99 a month

Details are on the pricing page. For one-off checks, use the email checker or the phone number validator.

The short version

Validate leads field by field with the right check for each: SMTP verification for email, format plus line-type lookup for phone, DNS and domain checks for company, and simple rules for names. Respect each check's limits: catch-all mailboxes cannot be confirmed and phone lookups cannot prove the person still answers. Score the whole record, route it to ready, review or reject, and never let one failed field throw away a reachable lead.