Company lists · Data refreshed September 2026
Top 25 Cold email infrastructure providers based in the United States
RevenueBase identified 168 cold email infrastructure providers headquartered in the United States as of September 2026 and tracks 1,557 professional contacts across them, including 414 with verified work emails and 356 with mobile numbers. New York is the largest hub.
This list covers cold email infrastructure 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 3, 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 cold email infrastructure providers based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 189 contacts → | ||||
Partial evidence “Sinch Mailgun is the leading email delivery service for businesses around the world.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 2 | 106 contacts → | ||||
Partial 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 3, 2026Thanks. The Data Team will review it. | |||||
| 3 | 103 contacts → | ||||
Partial evidence “Email Warm-Up & Deliverability Platform | Land in the Inbox, Not Spam Warmy is an AI-powered email deliverability platform trusted by businesses, marketers, and sales teams…” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 4 | 38 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 3, 2026Thanks. The Data Team will review it. | |||||
| 5 | 38 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 3, 2026Thanks. The Data Team will review it. | |||||
| 6 | 37 contacts → | ||||
Strong evidence “Maildoso provides high-quality SMTP and Google mailboxes built for cold email deliverability.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 7 | 32 contacts → | ||||
Strong evidence “Hunter is an all-in-one email outreach platform to identify relevant prospects, find their email addresses, and send cold email campaigns.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 8 | 28 contacts → | ||||
Partial evidence “Email Industries is a US-based email deliverability services provider that offers innovative products and services aimed at helping businesses like yours optimize their email…” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 9 | 25 contacts → | ||||
Partial 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 3, 2026Thanks. The Data Team will review it. | |||||
| 10 | 22 contacts → | ||||
Partial evidence “Inbox Monster helps email teams send epic messages to every inbox.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 11 | 20 contacts → | ||||
Partial 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 3, 2026Thanks. The Data Team will review it. | |||||
| 12 | 19 contacts → | ||||
Partial evidence “Email marketing is a powerful channel for small businesses to generate leads.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 13 | 18 contacts → | ||||
Partial evidence “Modern email delivery for developer and product teams in growing digital companies.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 14 | 17 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 3, 2026Thanks. The Data Team will review it. | |||||
| 15 | 14 contacts → | ||||
Partial evidence “At SendX, we’re passionate about making email marketing simple, affordable, and highly effective.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 16 | 13 contacts → | ||||
Partial evidence “Reliable and Secure email hosting services for SMB and Enterprise.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 17 | 13 contacts → | ||||
Partial evidence “Smarter, high-volume email delivery software for tech leaders & marketers.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 18 | 13 contacts → | ||||
Strong evidence “An AI-powered cold email outreach platform built for scale and deliverability.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 19 | 12 contacts → | ||||
Partial evidence “ReadyDedis is a company with over a decade of experience in providing and building high-performance infrastructure to provide the best possible experience for your online business.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 20 | 9 contacts → | ||||
Strong evidence “Senders is focused on email infrastructure, email scaling, email deliverability, and email sendability.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 21 | 8 contacts → | ||||
Partial evidence “The email delivery service that people actually like.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 22 | 7 contacts → | ||||
Partial evidence “Warmupinbox.com automatically raises your email sending reputation through our network of inboxes that talk to each other.” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 23 | 7 contacts → | ||||
Strong evidence “Mailforge sets up your email infrastructure (domains + mailboxes) within 5 minutes” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 24 | 5 contacts → | ||||
Indirect evidence “Since 2001, EmailOpen™ has been a leader in innovative electronic mail solutions, delivering proven and measurable results to the internal communication and direct marketing…” Source: RevenueBase Database · checked Sep 3, 2026Thanks. The Data Team will review it. | |||||
| 25 | 5 contacts → | ||||
Indirect evidence “Following are some of the features MassMailer provides for Salesforce CRM customers.” Source: RevenueBase Database · checked Sep 3, 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: cold email infrastructure 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 cold email infrastructure providers.
- Partial evidence
- Its own public description names part of cold email infrastructure providers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name cold email infrastructure 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 168 cold email infrastructure providers based in the United States
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Cold email infrastructure providers based in the United States at a glance
As of Sep 3, 2026Companies by employee count
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 cold email infrastructure 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 “cold email infrastructure 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 cold email infrastructure 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 cold email infrastructure 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, 414 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 3, 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 cold email infrastructure 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 cold email infrastructure providers are there based in the United States?
RevenueBase identified 168 cold email infrastructure 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?
Sinch Mailgun, headquartered in San Francisco, tops this list with the largest team on record.
Which city has the most cold email infrastructure providers?
New York leads with 16 headquartered companies, followed by Sheridan (11) and San Francisco (10).
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 414 verified decision-maker contacts tracked across these 168 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 3, 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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