Email deliverability makes or breaks outbound campaigns. A single bounce can hurt the sender reputation, and a bad list can stall entire outreach sequences. For B2B teams, that means lost conversations, wasted ad spend, and missed revenue.
One of the biggest challenges comes from catch-all domains. These are company inboxes set up to accept mail for any address, valid or not. Most verifiers simply mark them as “risky,” leaving sales and marketing teams to guess whether they’re worth sending to.
In this guide, you’ll learn what to look for in an email verifier, how catch-all results are handled, and the top tools to consider.
Picking the right verification tool is about more than just filtering out bad contacts. Teams need practical results they can act on quickly and trust at scale. Here are the factors that matter most:
A strong email verifier gives sales and marketing teams confidence in their outreach. With accurate results and actionable insights, you can protect sender reputation and improve campaign performance without second-guessing your data.
Choosing the right tool comes down to how well it handles catch-all emails, supports large lists, and integrates with the platforms you already use. Below, we’ll walk through the top options B2B teams can compare in 2025.
Listmint is built for B2B teams that need reliable verification at scale. Unlike most verifiers that stop at SMTP checks and mark catch-all domains as “risky,” Listmint verifies them in real time without sending test emails.
This allows businesses to recover leads that other tools throw away and reduce wasted spend on incomplete data.
Catch-all handling is where Listmint changes the game. On typical B2B lists, 30–40% of addresses are flagged as catch-all and left unused. Other services validate only ~55% of those contacts, while Listmint confirms up to 84% as valid, helping teams gain 50%+ more usable leads from the same list.
And instead of waiting 24–48 hours like with some providers, results come back instantly through the platform or API.
Performance also scales. With more than 1B emails verified and 99%+ SMTP and catch-all verification accuracy, Listmint is designed for both small business owners and enterprise teams.
For developers and resellers, the API provides real-time catch-all results with clear outputs like catch_all_valid and catch_all_invalid, supported by clean documentation, SDKs, and monitoring dashboards.
Listmint works directly for B2B teams running cold email campaigns and for B2B2C companies that need to resell verification services. The ability to verify catch-all emails instantly makes it a valuable option for anyone relying on accurate databases and deliverability.
"The fastest, easiest, and most effective validation tool"
SMTP + Catch-all validation in one platform - the most cost-effective + fastest way to get as many emails validated as possible
— Matt Lucero, Founder at Anevo Marketing
"The best platform for lead verification"
ListMint makes it extremely easy to verify email credits, both Standard & Catch-Alls, all in one platform. It saves my team hours of our time, being able to do it all in one place.
— Ryan S., CEO
"A Lifesaver for my lead Generation Agency"
It's the best platform for verifying emails, both in terms of cost and logistics. I run an agency with 40+ clients and was running around 70-80 cold email campaigns at a time. Using ListMint simplifies the email verification process and does a great job of only giving us valid emails so we can avoid email bounces. The ability to do both standard and catch-all email verification within the same platform is a game-changer.
— Liz M., Mirraponte Marketing
NeverBounce is an email verification service often used by businesses that manage large subscriber lists.
It checks email addresses against multiple points, including syntax, MX records, and domain status, to help identify invalid or inactive contacts. The platform also provides integrations with marketing platforms to help automate parts of the bulk email verification process.
For catch-all domains, NeverBounce typically returns them as “accept-all” without confirming inbox validity. This means teams still need to decide how to handle risky addresses in their campaigns.
Its setup makes it suitable for email marketers who want to clean existing databases or validate sign-up forms in real time.
NeverBounce can help reduce undeliverable emails and limit spam complaints by providing clear verification outputs. It fits companies focused on keeping contact data accurate while maintaining campaign performance.
Kickbox offers email verification software designed to help teams reduce invalid addresses in their contact data.
It checks syntax, domain records, and server responses, while also flagging role-based inboxes and disposable email addresses that may impact campaign performance. Many organizations use Kickbox for both bulk verification and ongoing database maintenance.
When working with domains that accept all incoming mail, Kickbox marks them as “accept-all” without confirming if the mailbox is active. Teams often treat these records as higher risk and decide whether to include them in campaigns depending on their own policies.
Kickbox helps teams monitor data quality by identifying undeliverable emails, disposable accounts, and other risky contacts. Its verification tool can be used across different marketing platforms to support cleaner databases and improve email deliverability.
MillionVerifier is an email validation service used to filter out invalid contacts and reduce undeliverable emails.
It runs checks across syntax, MX records, and domain health, giving teams a way to clean databases before launching campaigns. Many email marketers also use it for bulk uploads to improve email deliverability and campaign performance.
MillionVerifier lists catch-alls as “accept-all” without further confirmation of inbox activity. This limits precision for teams that want to separate valid contacts from invalid email addresses but still offers clarity on which addresses carry more risk.
MillionVerifier helps email marketers manage risky emails and filter disposable addresses before they impact sender reputation. Its verification tool supports both bulk email and single lookups, making it suitable for teams that want consistent database upkeep.
Clearout provides email verification software aimed at keeping databases accurate across different marketing platforms.
It checks addresses against syntax rules, MX records, and server responses to help filter invalid email addresses. The service is often applied to sign-up forms, bulk uploads, and contact databases used in ongoing campaigns.
Clearout marks catch-all domains as “accept-all” but does not verify whether an inbox actually exists. Teams use this output to decide how to manage those addresses in line with their own policies for risky contacts.
Clearout gives email marketers the ability to filter out invalid email and disposable emails while maintaining valid contacts for campaigns. Its outputs can be integrated into marketing platforms or stored in CRMs to support accurate contact data and campaign performance.
Verifalia provides email address verification through a web-based platform and API.
It runs multiple layers of checks, including syntax validation, DNS lookups, and server connections, to identify invalid email addresses and reduce undeliverable emails.
Many businesses use Verifalia to validate contact data in real time or process bulk uploads for campaign preparation.
Verifalia labels catch-all emails with an “accept-all” status without confirming the mailbox itself.
Teams often use these results as part of broader risk management, deciding how to handle uncertain records within their email campaigns.
Verifalia is often applied by email marketers who need both real-time validation and a bulk email verification process. The outputs help teams filter invalid email addresses, manage risky emails, and maintain valid contacts for ongoing campaigns.
MailerCheck is an email verification tool used to identify invalid email addresses and keep marketing databases clean.
It checks syntax, MX records, and domain health while also detecting disposable emails and spam traps that can affect campaign performance. Teams often apply it during bulk uploads or before launching new email campaigns.
For domains that accept all emails, MailerCheck categorizes them as “accept-all” without validating the individual inbox. This output helps teams understand potential risk levels and decide how those records should be treated within their own workflows.
MailerCheck provides verification results that support email marketers in reducing undeliverable emails and improving campaign performance. Its tools can be used for both bulk email verification and real-time checks, keeping contact data accurate for future campaigns.
For B2B teams, secure and accurate email verification is not just a preference; it is a requirement.
Listmint was built to meet that standard, providing developers and sales teams with a reliable API that delivers real-time results without exposing data to unnecessary risk. Its security posture, backed by enterprise compliance, makes it suitable for organizations that handle sensitive contact data at scale.
Unlike many email verification services that label catch-all domains as risky or accept-all, Listmint separates them into clear categories. Outputs such as catch_all_valid and catch_all_invalid allow teams to take immediate action without guessing.
In practice, this means more valid contacts can be included in campaigns, and fewer opportunities are lost to uncertainty. Testing shows that Listmint verifies 84% of catch-all leads as valid, compared to around 55% with other verifiers.
With 99%+ SMTP and catch-all validation accuracy across 1B+ verifications, Listmint gives teams confidence in their email address verification process. It fits into existing workflows while helping reduce risky emails, improve inbox placement, and protect sender reputation.
Getting verification results is only useful if you know how to apply them. Each status points to a clear action that helps protect the sender reputation and improve campaign performance.
With Listmint, catch-alls no longer require separate treatment. Once verified, they can be used just like any other valid contact. Removing the guesswork and helping you recover more leads confidently.
Keeping databases accurate is one of the simplest ways to protect sender reputation and improve inbox placement.
The right email verification tool helps sales and marketing teams reduce undeliverable emails, manage risky contacts, and focus on valid email addresses that move conversations forward.
For B2B teams, the challenge often comes down to how catch-all domains are handled. Most providers leave them unresolved, which means fewer usable leads and more uncertainty.
Listmint solves this gap with real-time outputs like catch_all_valid and catch_all_invalid, giving teams clear actions they can trust.
If your goal is to improve email deliverability, maintain accurate data, and get more out of your campaigns, Listmint provides a secure and scalable solution.
Sign up for a free account today and verify your first list with accurate, real-time results.
The best email verification tools provide accurate results for valid email addresses, disposable accounts, and risky domains. Listmint is often chosen by B2B teams because it verifies catch-all results in real time and offers secure API access.
Many providers also support flexible options such as pay-as-you-go or monthly subscription pricing.
Email authentication relies on protocols like SPF, DKIM, and DMARC to confirm that an email address exists and the email messages are legitimate. Tools like Listmint focus on verification, while mail verifier platforms help reduce spam complaints and improve inbox placement.
The best way to validate an email address is through an email verification service that checks syntax, MX records, and mailbox status. Using an online free email checker or a bulk email verifier helps identify invalid contacts.
Many providers also give email verification credits to test all the tools before scaling to larger lists.
Yes. Email validation tools confirm if an email address exists and can receive mail. A free email checker or email finder can verify single records, while a bulk verification tool processes larger datasets.
Look for services with a user-friendly interface that integrate with CRMs and marketing platforms for easier workflows.
Yes. Several providers let you start with a free account that includes limited email verification credits. Listmint offers this option so teams can test real-time catch-all verification, bulk uploads, and API integration before choosing a pay-as-you-go or monthly subscription plan.
