Company lists · Data refreshed September 2026
Top 25 Secure email gateway software companies based in the United States
RevenueBase identified 101 secure email gateway software companies headquartered in the United States as of September 2026 and tracks 1,793 professional contacts across them, including 515 with verified work emails. San Francisco is the largest hub.
This list covers secure email gateway software companies 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 secure email gateway software companies 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 | 129 contacts → | ||||
Strong 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. | |||||
| 4 | 67 contacts → | ||||
Indirect evidence “PreVeil makes encryption usable for CMMC & ITAR compliance, business and personal use.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 5 | 61 contacts → | ||||
Strong evidence “Paubox is a leader in HIPAA compliant email security for healthcare.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 6 | 53 contacts → | ||||
Indirect evidence “Cloudmark was acquired by Proofpoint.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 7 | 48 contacts → | ||||
Indirect evidence “ShelterZoom is a pioneering cybersecurity SaaS provider that transforms how organizations control, protect, and track their digital content.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 8 | 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. | |||||
| 9 | 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. | |||||
| 10 | 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. | |||||
| 11 | 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. | |||||
| 12 | 26 contacts → | ||||
Partial evidence “OPTIZMO Technologies is an innovative software company that provides robust, enterprise class solutions in the Fortune 500 arena.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 13 | 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. | |||||
| 14 | 19 contacts → | ||||
Partial evidence “Skysnag is a leading cybersecurity company pioneering real-time email authentication, offering the fastest comprehensive SaaS platform for DMARC, DKIM, SPF, BIMI, MTA-STS, and…” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 15 | 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. | |||||
| 16 | 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. | |||||
| 17 | 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. | |||||
| 18 | 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. | |||||
| 19 | 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. | |||||
| 20 | 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. | |||||
| 21 | 12 contacts → | ||||
Strong evidence “Reliable and Secure email hosting services for SMB and Enterprise.” Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 22 | 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. | |||||
| 23 | 10 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 14, 2026Thanks. The Data Team will review it. | |||||
| 24 | 10 contacts → | ||||
Strong 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. | |||||
| 25 | 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. | |||||
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: secure email gateway software companies. 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 secure email gateway software companies.
- Partial evidence
- Its own public description names part of secure email gateway software companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name secure email gateway software companies. 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 101 secure email gateway software companies based in the United States
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Secure email gateway software companies 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 101 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 secure email gateway software companies, 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 “secure email gateway software companies”. 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 secure email gateway software companies), 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 secure email gateway software companies, 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, 515 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 secure email gateway software companies, 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 secure email gateway software companies are there based in the United States?
RevenueBase identified 101 secure email gateway software companies 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 secure email gateway software companies?
San Francisco leads with 8 headquartered companies, followed by Chicago (5) and Miami (5).
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 515 verified decision-maker contacts tracked across these 101 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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