Company lists · Data refreshed September 2026
Top 25 Email security service providers based in the United States
RevenueBase identified 85 email security service providers headquartered in the United States as of September 2026 and tracks 1,838 professional contacts across them, including 408 with verified work emails. Miami is the largest hub.
This list covers email security service providers headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 14, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest email security service providers based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 236 contacts → | ||||
Strong evidence “Sublime is the new standard for email security.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 2 | 200 contacts → | ||||
Strong evidence “Zix, an OpenText company, is a leader in email security and helps organizations overcome their greatest digital transformation challenges by providing a secure, modern workplace.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 3 | 141 contacts → | ||||
Partial evidence “eSoft is a leader in providing Simply Better Network Security™ to businesses of nearly any size.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 4 | 129 contacts → | ||||
Partial evidence “EasyDMARC is your one-stop platform that secures your email domain infrastructure and boosts email deliverability for your peace of mind.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 5 | 53 contacts → | ||||
Indirect evidence “Cloudmark was acquired by Proofpoint.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 6 | 44 contacts → | ||||
Strong evidence “Mailprotector has built email security for the MSP channel for over 25 years on a fundamentally different premise: remove the conditions that create problems rather than defend…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 7 | 43 contacts → | ||||
Partial evidence “PowerDMARC empowers organizations to combat Business Email Compromise (BEC), email spoofing, and phishing with ease.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 8 | 39 contacts → | ||||
Partial evidence “Cyren, now part of Data443, protects hundreds of millions of users around the world from sophisticated and emerging email, malware, and web attacks every day.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 9 | 31 contacts → | ||||
Strong evidence “At Abusix, we empower businesses, ISPs, and email service providers with cutting-edge security solutions to safeguard digital infrastructure.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 10 | 26 contacts → | ||||
Partial evidence “Abnormal provides total protection against the widest range of email attacks including phishing, malware, ransomware, social engineering, executive impersonation, supply chain…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 11 | 23 contacts → | ||||
Strong evidence “Cloudflare Area 1 is a cloud-native email security service that identifies and blocks attacks before they hit user inboxes, enabling more effective protection against spear…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 12 | 19 contacts → | ||||
Strong evidence “SafeGuard Cyber provides security and compliance for email and multi-channel communications.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 13 | 19 contacts → | ||||
Partial evidence “Founded in 2003, Sendio is a venture-backed, privately held company whose products protect the email environments of enterprises and institutions from attacks and abuse, and…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 14 | 16 contacts → | ||||
Strong evidence “MailGate SC is a comprehensive email security solution that protects your organization from a wide range of advanced threats.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 15 | 15 contacts → | ||||
Strong evidence “Spambrella is a Worldwide email content control security ‘software as a service’ (SaaS) provider.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 16 | 15 contacts → | ||||
Strong evidence “EdgeWave is hyper-focused on delivering the World’s Safest Inboxes™ by eliminating email-borne security risks for organizations in the face of targeted, socially engineered…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 17 | 14 contacts → | ||||
Partial evidence “Agari is the Trusted Email Identity Company™, protecting brands and people from devastating phishing and socially-engineered attacks.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 18 | 14 contacts → | ||||
Indirect evidence “Maysoft has been stopping spam and viruses for over 10 years.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 19 | 12 contacts → | ||||
Partial evidence “Reliable and Secure email hosting services for SMB and Enterprise.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 20 | 12 contacts → | ||||
Partial evidence “Global companies use GreatHorn to reduce the inherent and pervasive risk associated with the everyday use of email.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 21 | 10 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 22 | 10 contacts → | ||||
Partial evidence “At Identillect Technologies, we create a user-friendly secure email solution to protect critical information, with an emphasis on simplicity.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 23 | 10 contacts → | ||||
Partial evidence “At InQuest, we specialize in providing comprehensive network-based security solutions that empower organizations to protect their most critical assets: their people.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 24 | 9 contacts → | ||||
Partial evidence “StealthMail makes your emails secure and invisible to email relays, hackers, or Public Internet threats - making email relationships with clients a trusted one via StealthMail’s…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 25 | 8 contacts → | ||||
Indirect evidence “Down-to earth Cloud services.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: email security service providers. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names email security service providers.
- Partial evidence
- Its own public description names part of email security service providers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name email security service providers. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 85 email security service providers based in the United States
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Email security service providers based in the United States at a glance
As of Sep 14, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 85 companies.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among email security service providers, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United States whose own description of what they do matches “email security service providers”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names email security service providers), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among email security service providers, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 408 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 14, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names email security service providers, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many email security service providers are there based in the United States?
RevenueBase identified 85 email security service providers headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
Sublime Security, headquartered in Washington, tops this list with the largest team on record.
Which city has the most email security service providers?
Miami leads with 5 headquartered companies, followed by San Francisco (5) and New York (4).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 408 verified decision-maker contacts tracked across these 85 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 14, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.
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