Company lists · Data refreshed September 2026

Top 13 Inbox placement software companies based in the United Kingdom

RevenueBase identified 34 inbox placement software companies headquartered in the United Kingdom as of September 2026 and tracks 131 professional contacts across them, including 41 with verified work emails and 6 with mobile numbers. London is the largest hub.

This list covers inbox placement software companies 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, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 13, 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 13, 2026 86% judged on-target in blind review
34Companies
131Contacts tracked
41Verified emails
6Mobile numbers
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The 13 largest inbox placement software companies based in the United Kingdom

Ranked by team size
Top 13 of 34 inbox placement software companies based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 13, 2026. RevenueBase Smart Search rates how each company's information relates to inbox placement 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
1Indirect evidenceLondon, United KingdomHQ checked Sep 13, 202611-5030 contacts →

Indirect evidence

“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: RevenueBase Database · checked Sep 13, 2026
2Indirect evidenceLondon, United KingdomHQ checked Sep 13, 202611-5013 contacts →

Indirect evidence

“iNBOTiQA is the next-generation Intelligent Business Email for high-volume and group mailboxes.”

Source: RevenueBase Database · checked Sep 13, 2026
3Indirect evidenceAshford, United KingdomHQ checked Sep 13, 202611-508 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 13, 2026
4Indirect evidenceLondon, United KingdomHQ checked Sep 13, 20261-106 contacts →

Indirect evidence

“Unlock unprecedented growth with Power Play's revolutionary email strategies.”

Source: RevenueBase Database · checked Sep 13, 2026
5Partial evidenceTowcester, United KingdomHQ checked Sep 13, 202611-504 contacts →

Partial evidence

“Email Blaster UK offer cloud based email marketing software.”

Source: RevenueBase Database · checked Sep 13, 2026
6Indirect evidenceLondon, United KingdomHQ checked Sep 13, 20261-103 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 13, 2026
7Indirect evidenceChesterfield, United KingdomHQ checked Sep 13, 202611-502 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 13, 2026
8Indirect evidenceCroydon, United KingdomHQ checked Sep 13, 20261-102 contacts →

Indirect evidence

“WizEmail is an email marketing company formed by marketing specialists totalling decades of years experience in the direct marketing, internet and publishing sectors.”

Source: RevenueBase Database · checked Sep 13, 2026
9Partial evidenceLondon, United KingdomHQ checked Sep 13, 20261-102 contacts →

Partial evidence

“We've reimagined email marketing, distilling years of agency expertise into software.”

Source: RevenueBase Database · checked Sep 13, 2026
10Indirect evidenceLondon, United KingdomHQ checked Sep 13, 20261-102 contacts →

Indirect evidence

“Helping Recruiters With Email Deliverability.”

Source: RevenueBase Database · checked Sep 13, 2026
11Indirect evidenceLondon, United KingdomHQ checked Sep 13, 20261-101 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 13, 2026
12Partial evidenceLondon, United KingdomHQ checked Sep 13, 20261-101 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 13, 2026
13Indirect evidenceLondon, United KingdomHQ checked Sep 13, 20261-101 contacts →

Indirect evidence

“MailPimps’ reason for existence is to take tired, unloved email campaigns and pimp them up!”

Source: RevenueBase Database · checked Sep 13, 2026

Showing 13 of 34 inbox placement software companies based in the United Kingdom

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Inbox placement software companies based in the United Kingdom at a glance

As of Sep 13, 2026
31.3%Verified-email coverage
4.6%Mobile-number coverage
3.9Average contacts per company
1-10Median size (employees)
52.9%Largest-city concentration · London
Sep 13, 2026Page data refreshed

Companies by employee count

1-10
24
11-50
7
51-200
1
201-500
2

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 16.0d

Company record updated

Median 65.0d

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 inbox placement 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 Kingdom whose own description of what they do matches “inbox placement 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 inbox placement 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 inbox placement software companies, 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 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, 41 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 13, 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 inbox placement 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 inbox placement software companies are there based in the United Kingdom?

RevenueBase identified 34 inbox placement software companies 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 inbox placement software companies?

London leads with 18 headquartered companies, followed by Ashford (1) and Burcote (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 41 verified decision-maker contacts tracked across these 34 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 13, 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.