Company lists · Data refreshed September 2026

Top 25 Transactional email software companies based in the United States

RevenueBase identified 162 transactional email software companies headquartered in the United States as of September 2026 and tracks 2,169 professional contacts across them, including 737 with verified work emails. New York is the largest hub.

This list covers transactional email 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 14, 2026 86% judged on-target in blind review
162Companies
2,169Contacts tracked
737Verified emails
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The 25 largest transactional email software companies based in the United States

Ranked by team size
Top 25 of 162 transactional email software companies based in the United States, ranked by team size, largest first. Data refreshed Sep 14, 2026. RevenueBase Smart Search rates how each company's information relates to transactional email software companies: 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
1Partial evidenceSan Antonio, TX, United StatesHQ checked Sep 14, 2026201-500190 contacts →

Partial evidence

“Sinch Mailgun is the leading email delivery service for businesses around the world.”

Source: RevenueBase Database · checked Sep 14, 2026
2Indirect evidenceMorrisville, NC, United StatesHQ checked Sep 14, 202651-200137 contacts →

Indirect evidence

“We believe powerful connections propel business growth.”

Source: RevenueBase Database · checked Sep 14, 2026
3Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 14, 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 14, 2026
4Partial evidenceSt Louis, MO, United StatesHQ checked Sep 14, 202651-200115 contacts →

Partial evidence

“Benchmark helps busy marketers move faster and make a bigger impact with email.”

Source: RevenueBase Database · checked Sep 14, 2026
5Partial evidenceDoylestown, PA, United StatesHQ checked Sep 14, 202651-20090 contacts →

Partial evidence

“For over 20 years, AWeber has helped entrepreneurs and small business owners connect with their prospects and customers through powerfully-simple email marketing solutions.”

Source: RevenueBase Database · checked Sep 14, 2026
6Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 14, 202611-5088 contacts →

Partial evidence

“Mailmodo is a complete email marketing solution enabling users to create and send app-like interactive emails to improve email conversions.”

Source: RevenueBase Database · checked Sep 14, 2026
7Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 14, 202651-20080 contacts →

Partial evidence

“Flodesk makes simple, intuitive software tools to help entrepreneurs grow their businesses.”

Source: RevenueBase Database · checked Sep 14, 2026
8Indirect evidenceCambridge, MA, United StatesHQ checked Sep 14, 202651-20070 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 14, 2026
9Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 14, 202611-5056 contacts →

Partial evidence

Email for developers”

Source: RevenueBase Database · checked Sep 14, 2026
10Partial evidenceSan Mateo, CA, United StatesHQ checked Sep 14, 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 14, 2026
11Partial evidenceDenver, CO, United StatesHQ checked Sep 14, 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 14, 2026
12Partial evidenceSeattle, NC, United StatesHQ checked Sep 14, 202651-20037 contacts →

Partial evidence

“WhatCounts is an email marketing and personalization platform empowering marketers to elevate customer targeting and daily email strategy and execution.”

Source: RevenueBase Database · checked Sep 14, 2026
13Partial evidenceBoise, ID, United StatesHQ checked Sep 14, 202651-20036 contacts →

Partial evidence

“Kit (formerly ConvertKit) helps serious creators like yourself craft epic emails, create powerful automations, and manage their audience all in a simple, intuitive platform.”

Source: RevenueBase Database · checked Sep 14, 2026
14Partial evidenceDover, DE, United StatesHQ checked Sep 14, 202651-20029 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 14, 2026
15Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 14, 202611-5026 contacts →

Partial evidence

“Empower your team to create, innovate, and grow with the Dyspatch Email Builder.”

Source: RevenueBase Database · checked Sep 14, 2026
16Partial evidenceCarmel, IN, United StatesHQ checked Sep 14, 202611-5025 contacts →

Partial evidence

“Delivra, a Redbrick company, is a sophisticated email platform that designs custom solutions to help marketers and agencies automate highly personalized, event-driven campaigns…”

Source: RevenueBase Database · checked Sep 14, 2026
17Strong evidencePinedale, WY, United StatesHQ checked Sep 14, 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 14, 2026
18Partial evidenceWilmington, DE, United StatesHQ checked Sep 14, 202611-5020 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 14, 2026
19Indirect evidenceNew Orleans, LA, United StatesHQ checked Sep 14, 202611-5019 contacts →

Indirect evidence

“Our newsletters engage your customers through curated content and help build relationships.”

Source: RevenueBase Database · checked Sep 14, 2026
20Partial evidenceLos Angeles, CA, United StatesHQ checked Sep 14, 202651-20019 contacts →

Partial evidence

“Modern email delivery for developer and product teams in growing digital companies.”

Source: RevenueBase Database · checked Sep 14, 2026
21Indirect evidenceNew York, NY, United StatesHQ checked Sep 14, 202611-5016 contacts →

Indirect evidence

“Robly is a fast-growing remote start-up.”

Source: RevenueBase Database · checked Sep 14, 2026
22Partial evidenceWilmington, DE, United StatesHQ checked Sep 14, 202611-5014 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 14, 2026
23Partial evidenceWayne, PA, United StatesHQ checked Sep 14, 202611-5013 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 14, 2026
24Strong evidenceSchneider, IN, United StatesHQ checked Sep 14, 202611-5013 contacts →

Strong evidence

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

Source: RevenueBase Database · checked Sep 14, 2026
25Partial evidenceSan Antonio, TX, United StatesHQ checked Sep 14, 2026201-50012 contacts →

Partial evidence

“Drive smart results with flexible APIs and intuitive tools to power your email communication.”

Source: RevenueBase Database · checked Sep 14, 2026

Showing 25 of 162 transactional email software companies based in the United States

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Transactional email software companies based in the United States at a glance

As of Sep 14, 2026
34.0%Verified-email coverage
13.4Average contacts per company
11-50Median size (employees)
10.5%Largest-city concentration · New York
Sep 14, 2026Page data refreshed

Companies by employee count

1-10
77
11-50
56
51-200
19
201-500
7
1,001-5,000
3

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 162 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 transactional email 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 “transactional email 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 transactional email 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 transactional email 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, 737 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 transactional email 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 transactional email software companies are there based in the United States?

RevenueBase identified 162 transactional email 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?

Sinch Mailgun, headquartered in San Antonio, tops this list with the largest team on record.

Which city has the most transactional email software companies?

New York leads with 17 headquartered companies, followed by Austin (11) and San Francisco (8).

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 737 verified decision-maker contacts tracked across these 162 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.