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Glossary

The email & data verification glossary

Plain-English definitions for everything in email verification, phone validation, deliverability and contact data. Pick a term to learn what it means and what to do about it.

Email verification

The process of checking whether an email address is real and able to receive mail, without sending one.

Catch-all email

A domain configured to accept mail for every address, so a verifier can't confirm a specific mailbox exists.

Disposable email

A temporary, throwaway address from a service designed to self-destruct after short-term use.

Hard bounce vs soft bounce

A hard bounce is a permanent delivery failure; a soft bounce is a temporary one.

Sender reputation

A trust score mailbox providers assign to your sending domain and IP that decides inbox vs spam.

Spam trap

An email address used by providers and blocklists to catch senders with poor list hygiene.

Role-based email

An address tied to a function rather than a person, like info@ or sales@.

MX record

A DNS record that tells other servers where to deliver email for a domain.

SPF

Sender Policy Framework — a DNS record listing which servers may send email for your domain.

DKIM

DomainKeys Identified Mail — a cryptographic signature that proves an email wasn't altered in transit.

DMARC

A policy that tells receivers what to do with mail failing SPF and DKIM, plus where to send reports.

Email deliverability

Whether your email actually reaches the inbox rather than the spam folder or a bounce.

Phone number validation

Checking whether a phone number is correctly formatted, active and what line type it is.

HLR lookup

A query against the carrier's Home Location Register to check a mobile number's live status.

Line type (mobile/landline/VoIP)

Whether a phone number is a mobile, a landline or a VoIP number — which changes how you should reach it.

Data enrichment

Adding missing context — like company, industry or location — to a contact record.

Firmographics

Company-level attributes — industry, size, revenue, location — used to segment and score B2B leads.

Company name-to-domain matching

Resolving a company's name to its primary web domain, a building block of B2B enrichment.

Bounce rate

The share of sent emails that couldn't be delivered — a key deliverability signal.

List hygiene

The ongoing practice of keeping a contact list clean, current and deliverable.

Email verification API

A programmatic endpoint that verifies an address in real time, usually at the point of capture.

Form guard

Real-time verification on a signup or lead form that blocks fake, invalid or risky submissions.

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