Company lists · Data refreshed September 2026

Top 25 Transactional email services based in the United States

RevenueBase identified 71 transactional email services headquartered in the United States as of September 2026 and tracks 1,840 professional contacts across them, including 729 with verified work emails. New York is the largest hub.

This list covers transactional email services 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 22, 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 22, 2026 86% judged on-target in blind review
71Companies
1,840Contacts tracked
729Verified emails
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest transactional email services based in the United States

Ranked by team size
Top 25 of 71 transactional email services based in the United States, ranked by team size, largest first. Data refreshed Sep 22, 2026. RevenueBase Smart Search rates how each company's information relates to transactional email services: 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 evidencePortland, OR, United StatesHQ checked Sep 22, 2026201-500446 contacts →

Indirect evidence

“Create personalized customer journeys that engage and convert with our versatile customer engagement platform.”

Source: RevenueBase Database · checked Sep 22, 2026
2Indirect evidenceNew York, NY, United StatesHQ checked Sep 22, 202651-200197 contacts →

Indirect evidence

“Our mission is to solve customer experience.”

Source: RevenueBase Database · checked Sep 22, 2026
3Partial evidenceSan Antonio, TX, United StatesHQ checked Sep 22, 2026201-500190 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
4Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 22, 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 22, 2026
5Partial evidenceSt Louis, MO, United StatesHQ checked Sep 22, 202651-200115 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
6Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 22, 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 22, 2026
7Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 22, 202611-5056 contacts →

Partial evidence

Email for developers”

Source: RevenueBase Database · checked Sep 22, 2026
8Partial evidenceSan Diego, CA, United StatesHQ checked Sep 22, 202651-20046 contacts →

Partial evidence

“Truly unified email, SMS, reviews, and forms.”

Source: RevenueBase Database · checked Sep 22, 2026
9Partial evidenceDenver, CO, United StatesHQ checked Sep 22, 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 22, 2026
10Partial evidenceBoise, ID, United StatesHQ checked Sep 22, 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 22, 2026
11Indirect evidenceNew York, United StatesHQ checked Sep 22, 202611-5027 contacts →

Indirect evidence

“Knock is infrastructure for sending product and customer messaging.”

Source: RevenueBase Database · checked Sep 22, 2026
12Partial evidenceCarmel, IN, United StatesHQ checked Sep 22, 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 22, 2026
13Indirect evidenceNew Orleans, LA, United StatesHQ checked Sep 22, 202611-5019 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
14Partial evidenceLos Angeles, CA, United StatesHQ checked Sep 22, 202651-20019 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
15Indirect evidenceNew York, NY, United StatesHQ checked Sep 22, 202611-5016 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
16Partial evidenceWilmington, DE, United StatesHQ checked Sep 22, 202611-5014 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 22, 2026
17Partial evidenceWayne, PA, United StatesHQ checked Sep 22, 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 22, 2026
18Partial evidenceBeaverton, OR, United StatesHQ checked Sep 22, 20261-109 contacts →

Partial evidence

“Loops helps SaaS businesses send beautiful email newsletters, automated messages and one-off campaigns in a simple, easy to use interface.”

Source: RevenueBase Database · checked Sep 22, 2026
19Indirect evidenceNew York, NY, United StatesHQ checked Sep 22, 20261-109 contacts →

Indirect evidence

“Zapier for Notifications.”

Source: RevenueBase Database · checked Sep 22, 2026
20Partial evidenceChicago, IL, United StatesHQ checked Sep 22, 202611-508 contacts →

Partial evidence

“The email delivery service that people actually like.”

Source: RevenueBase Database · checked Sep 22, 2026
21Partial evidenceNewark, DE, United StatesHQ checked Sep 22, 202651-2005 contacts →

Partial evidence

“MailBluster began its journey in 2015 by building its platform on cutting-edge technology to deliver high-volume marketing emails at affordable prices.”

Source: RevenueBase Database · checked Sep 22, 2026
22Strong evidenceNew York, NY, United StatesHQ checked Sep 22, 20261-105 contacts →

Strong evidence

“MailerSend is a powerful transactional email system built for developers but designed so non-tech teams can contribute without coding.”

Source: RevenueBase Database · checked Sep 22, 2026
23Partial evidenceScottsdale, AZ, United StatesHQ checked Sep 22, 202611-505 contacts →

Partial evidence

“Acquired by GoDaddy in 2014, Mad Mimi is a lovely, simple email service that lets you create, send and track email newsletters.”

Source: RevenueBase Database · checked Sep 22, 2026
24Partial evidencePlymouth, MI, United StatesHQ checked Sep 22, 202611-504 contacts →

Partial evidence

“Helm Technologies (formerly Chatterspot) specializes in automated text and email marketing that leverages deep data insights and predictive customer buying patterns within CRM…”

Source: RevenueBase Database · checked Sep 22, 2026
25Indirect evidenceCharlotte, NC, United StatesHQ checked Sep 22, 202611-504 contacts →

Indirect evidence

“PITCHcrm is a marketing platform that integrates directly with the heart of your business – your Point of Sale.”

Source: RevenueBase Database · checked Sep 22, 2026

Showing 25 of 71 transactional email services based in the United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 729 reachable decision-makers.

Free signup · no credit card

View the full list →

Transactional email services based in the United States at a glance

As of Sep 22, 2026
39.6%Verified-email coverage
25.9Average contacts per company
11-50Median size (employees)
14.1%Largest-city concentration · New York
Sep 22, 2026Page data refreshed

Companies by employee count

1-10
31
11-50
25
51-200
10
201-500
4
1,001-5,000
1

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 71 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 services, 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 services”. 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 services), 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 services, 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, 729 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 22, 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 services, 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 services are there based in the United States?

RevenueBase identified 71 transactional email services 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?

customer.io, headquartered in Portland, tops this list with the largest team on record.

Which city has the most transactional email services?

New York leads with 10 headquartered companies, followed by Austin (8) and San Francisco (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 729 verified decision-maker contacts tracked across these 71 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 22, 2026.

Ready to reach these companies? Verified emails and direct dials for all 71 transactional email services based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

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.