Company lists · Data refreshed September 2026

Top 12 Cold email infrastructure providers based in the United Kingdom

RevenueBase identified 38 cold email infrastructure providers headquartered in the United Kingdom as of September 2026 and tracks 196 professional contacts across them, including 54 with verified work emails and 6 with mobile numbers. London is the largest hub.

This list covers cold email infrastructure providers headquartered in the United Kingdom, 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, how directly it supports the match, 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 SmartSearch, 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 Match evidence on every row Refreshed Sep 3, 2026 86% judged on-target in blind review
38Companies
196Contacts tracked
54Verified emails
6Mobile numbers
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The 12 largest cold email infrastructure providers based in the United Kingdom

Ranked by team size
Top 12 of 38 cold email infrastructure providers based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 3, 2026. Evidence rates how directly each company's own description names cold email infrastructure providers: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#CompanyHeadquartersEmployeesContacts
1
MailercloudPartial evidence
London, United Kingdom11-5030

“Since 2013, mailercloud has expanded to become one of the largest and most extensive cloud-based email services, that resolves the task of reliably delivering emails on behalf of…”

Source: company website · checked Sep 3, 2026
2
Folderly INCPartial evidence
London, United Kingdom51-20029

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

Source: company website · checked Sep 3, 2026
3Stratford Upon Avon, United Kingdom11-5028

“Eloquent operates a range of platforms across various secure data centres in the UK, all of which are connected to our network and serve as the delivery point for our services.”

Source: company website · checked Sep 3, 2026
4
MailxpertisePartial evidence
Ashford, United Kingdom11-508

“We are MailXpertise, a global ESP (email service provider), specialists in made-to-measure email and SMS solutions for marketing professionals.”

Source: company website · checked Sep 3, 2026
5
Leveraged OutboundIndirect evidence
London, United Kingdom1-106

“Most B2B service businesses don't have a pipeline problem.”

Source: company website · checked Sep 3, 2026
6
KumomtaStrong evidence
London, United Kingdom1-104

“KumoMTA is the open-source email infrastructure for enterprises and high-volume senders who want control and continuity without the risk, volatility, or pricing shocks that come…”

Source: company website · checked Sep 3, 2026
7
MailyserPartial evidence
London, United Kingdom1-103

“About Us: At Mailyser, we are passionate about helping businesses and individuals maximize their email marketing potential.”

Source: company website · checked Sep 3, 2026
8
247emaildataPartial evidence
Chesterfield, United Kingdom11-502

“An Enterprise class email marketing platform, providing industry leading delivery rates.”

Source: company website · checked Sep 3, 2026
9
QuinsetPartial evidence
London, United Kingdom1-102

“Helping Recruiters With Email Deliverability.”

Source: company website · checked Sep 3, 2026
10
CloudessencePartial evidence
Newhaven, United Kingdom1-102

“Whether you need a single Email account for your small business or a Virtual DataCentre for your large enterprise, we have the experience and skills to provide you with trusted…”

Source: company website · checked Sep 3, 2026
11
InboxwizardsPartial evidence
London, United Kingdom1-101

“InboxWizards help small to large email senders deliver their emails to the Inbox.”

Source: company website · checked Sep 3, 2026
12
RED Circle DigitalPartial evidence
London, United Kingdom1-101

“Red Circle Digital will help you get the most from your email marketing.”

Source: company website · checked Sep 3, 2026

Showing 12 of 38 cold email infrastructure providers based in the United Kingdom

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Cold email infrastructure providers based in the United Kingdom at a glance

As of Sep 3, 2026
1-10Median size (employees)
LondonLargest hub · 23 HQs
6Contacts with mobile numbers
Sep 3, 2026Data refreshed

Companies by employee count

1-10
27
11-50
6
51-200
2
201-500
2

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 evidence 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 SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United Kingdom 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.
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 Kingdom 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 an evidence 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, 54 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

How many cold email infrastructure providers are there based in the United Kingdom?

RevenueBase identified 38 cold email infrastructure providers headquartered in the United Kingdom 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?

Mailercloud, headquartered in London, tops this list with the largest team on record.

Which city has the most cold email infrastructure providers?

London leads with 23 headquartered companies, followed by Cambridge (1) and Manchester (1).

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 54 verified decision-maker contacts tracked across these 38 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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Related lists

Cold email infrastructure providers by geography

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 SmartSearch, 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.