Company lists · Data refreshed September 2026

Top 25 Email deliverability tool vendors based in the United States

RevenueBase identified 165 email deliverability tool vendors headquartered in the United States as of September 2026 and tracks 1,830 professional contacts across them, including 529 with verified work emails. San Francisco is the largest hub.

This list covers email deliverability tool vendors 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 19, 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 19, 2026 86% judged on-target in blind review
165Companies
1,830Contacts tracked
529Verified emails
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The 25 largest email deliverability tool vendors based in the United States

Ranked by team size
Top 25 of 165 email deliverability tool vendors based in the United States, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to email deliverability tool vendors: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceMorrisville, NC, United StatesHQ checked Sep 19, 202651-200137 contacts →

Indirect evidence

“We believe powerful connections propel business growth.”

Source: RevenueBase Database · checked Sep 19, 2026
2Strong evidenceDover, DE, United StatesHQ checked Sep 19, 202651-200129 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 19, 2026
3Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 202651-200122 contacts →

Partial evidence

“In 2005, we started as a web design agency, but we soon discovered email marketing and fell in love with it.”

Source: RevenueBase Database · checked Sep 19, 2026
4Strong evidenceSanta Barbara, CA, United StatesHQ checked Sep 19, 202651-200105 contacts →

Strong evidence

“ZeroBounce is an email validation, deliverability and email finding platform helping businesses reduce bounces and land their emails in the inbox.”

Source: RevenueBase Database · checked Sep 19, 2026
5Indirect evidenceCambridge, MA, United StatesHQ checked Sep 19, 202651-20070 contacts →

Indirect evidence

“At Litmus, we know the importance of continuous innovation.”

Source: RevenueBase Database · checked Sep 19, 2026
6Partial evidenceSan Mateo, CA, United StatesHQ checked Sep 19, 202651-20039 contacts →

Partial evidence

“iPost is a leading email-sending platform purpose-built to solve real challenges in highly regulated and other data- and content-sensitive industries, including gaming, legal…”

Source: RevenueBase Database · checked Sep 19, 2026
7Partial evidenceDenver, CO, United StatesHQ checked Sep 19, 2026201-50038 contacts →

Partial evidence

“SendGrid is a proven cloud-based customer communication platform that successfully delivers over 45 billion emails each month for Internet and mobile-based customers like Airbnb…”

Source: RevenueBase Database · checked Sep 19, 2026
8Strong evidenceGranite Bay, CA, United StatesHQ checked Sep 19, 202611-5037 contacts →

Strong evidence

“Maildoso provides high-quality SMTP and Google mailboxes built for cold email deliverability.”

Source: RevenueBase Database · checked Sep 19, 2026
9Partial evidenceCentennial, CO, United StatesHQ checked Sep 19, 202611-5036 contacts →

Partial evidence

“Put your best email forward with Email on Acid!”

Source: RevenueBase Database · checked Sep 19, 2026
10Strong evidenceDover, DE, United StatesHQ checked Sep 19, 202651-20029 contacts →

Strong evidence

“Folderly is an all-in-one email deliverability platform to supercharge your email performance.”

Source: RevenueBase Database · checked Sep 19, 2026
11Strong evidencePinedale, WY, United StatesHQ checked Sep 19, 202611-5025 contacts →

Strong evidence

“GlockApps Software is a privately held company that offers multiple email marketing solutions to help businesses reach the inbox and solve email deliverability issues.”

Source: RevenueBase Database · checked Sep 19, 2026
12Partial evidenceCharlotte, NC, United StatesHQ checked Sep 19, 202611-5023 contacts →

Partial evidence

“Inbox Monster helps email teams send epic messages to every inbox.”

Source: RevenueBase Database · checked Sep 19, 2026
13Strong evidenceDallas, TX, United StatesHQ checked Sep 19, 202611-5021 contacts →

Strong evidence

“Kickbox provides technology that promotes email best practices and improves inbox placement, including a full suite of deliverability monitoring and management tools.”

Source: RevenueBase Database · checked Sep 19, 2026
14Partial evidenceExton, PA, United StatesHQ checked Sep 19, 202611-5020 contacts →

Partial evidence

Email Meter is an all-in-one email analytics solution that helps teams and individuals make a better use of email.”

Source: RevenueBase Database · checked Sep 19, 2026
15Partial evidenceWilmington, DE, United StatesHQ checked Sep 19, 202611-5020 contacts →

Partial evidence

Email marketing is a powerful channel for small businesses to generate leads.”

Source: RevenueBase Database · checked Sep 19, 2026
16Partial evidenceWilmington, DE, United StatesHQ checked Sep 19, 202611-5014 contacts →

Partial evidence

“At SendX, we’re passionate about making email marketing simple, affordable, and highly effective.”

Source: RevenueBase Database · checked Sep 19, 2026
17Strong evidenceMiami, FL, United StatesHQ checked Sep 19, 202611-5014 contacts →

Strong evidence

“The team behind the email verification tool you’ve been searching for.”

Source: RevenueBase Database · checked Sep 19, 2026
18Strong evidenceWayne, PA, United StatesHQ checked Sep 19, 202611-5013 contacts →

Strong evidence

“SocketLabs is an email service provider with a full suite of email delivery, management, and performance analysis tools.”

Source: RevenueBase Database · checked Sep 19, 2026
19Partial evidenceSchneider, IN, United StatesHQ checked Sep 19, 202611-5013 contacts →

Partial evidence

“Smarter, high-volume email delivery software for tech leaders & marketers.”

Source: RevenueBase Database · checked Sep 19, 2026
20Strong evidenceBrooklyn, NY, United StatesHQ checked Sep 19, 202611-5011 contacts →

Strong evidence

“Senders is focused on email infrastructure, email scaling, email deliverability, and email sendability.”

Source: RevenueBase Database · checked Sep 19, 2026
21Partial evidenceDenver, CO, United StatesHQ checked Sep 19, 20261-1010 contacts →

Partial evidence

“Our specialization: Ensure reliable and efficient delivery of emails.”

Source: RevenueBase Database · checked Sep 19, 2026
22Strong evidenceMiami, FL, United StatesHQ checked Sep 19, 20261-1010 contacts →

Strong evidence

“SH supports companies by improving email deliverability, detecting and mitigating security risks, and architecting sending infrastructure for sustainable scale and growth.”

Source: RevenueBase Database · checked Sep 19, 2026
23Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 20261-1010 contacts →

Partial evidence

“As spam filters tighten, 52% of business emails go unseen, crippling sales and collections for B2B companies.”

Source: RevenueBase Database · checked Sep 19, 2026
24Partial evidenceGlendale, CA, United StatesHQ checked Sep 19, 202611-509 contacts →

Partial evidence

“EmailOversight provides advanced email validation, threat assessment, and data append services that scale with your business.”

Source: RevenueBase Database · checked Sep 19, 2026
25Indirect evidenceChattanooga, TN, United StatesHQ checked Sep 19, 202611-509 contacts →

Indirect evidence

“AudiencePoint is an engagement intelligence company built for high-stakes moments-when performance, budgets, and deadlines don’t allow guesswork.”

Source: RevenueBase Database · checked Sep 19, 2026

Showing 25 of 165 email deliverability tool vendors based in the United States

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Email deliverability tool vendors based in the United States at a glance

As of Sep 19, 2026
28.9%Verified-email coverage
11.1Average contacts per company
11-50Median size (employees)
8.5%Largest-city concentration · San Francisco
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
82
11-50
64
51-200
13
201-500
6

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 165 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 deliverability tool vendors, 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 deliverability tool vendors”. 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 deliverability tool vendors), 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 deliverability tool vendors, 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, 529 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 19, 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 deliverability tool vendors, 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 deliverability tool vendors are there based in the United States?

RevenueBase identified 165 email deliverability tool vendors 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?

Icontact, headquartered in Morrisville, tops this list with the largest team on record.

Which city has the most email deliverability tool vendors?

San Francisco leads with 14 headquartered companies, followed by New York (11) and Austin (9).

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 529 verified decision-maker contacts tracked across these 165 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 19, 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.