Company lists · Data refreshed August 2026

Top 25 Cloud communications companies based in London, United Kingdom

Name: Cloud communications companies based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Aug 30, 2026 69 companies tracked

RevenueBase identified 69 cloud communications companies headquartered in London, United Kingdom as of August 2026 and tracks 2,511 professional contacts across them, including 914 with verified work emails and 427 with mobile numbers. London is the largest hub.

This list covers cloud communications companies headquartered in London, 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 August 30, 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 RevenueBase Smart Search rating on every row Refreshed Aug 30, 2026 86% judged on-target in blind review

69Companies

2,511Contacts tracked

914Verified emails

427Mobile numbers

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The 25 largest cloud communications companies based in London, United Kingdom

Ranked by team size

Top 25 of 69 cloud communications companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Aug 30, 2026. RevenueBase Smart Search rates how each company's information relates to cloud communications 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Kaltura	Indirect evidence	London, United Kingdom	501-1,000	734 contacts →
	Indirect evidence “Kaltura’s mission is to power any video experience for any organization.” Source: RevenueBase Database · checked Aug 30, 2026
2	Imimobile Part Of Webex	Indirect evidence	London, United Kingdom	1,001-5,000	436 contacts →
	Indirect evidence “We've moved!” Source: RevenueBase Database · checked Aug 30, 2026
3	Calltower	Strong evidence	London, United Kingdom	201-500	226 contacts →
	Strong evidence “Since 2002, CallTower has been at the forefront of transforming global communication, emerging as a leader in enterprise-class cloud communication, collaboration, and CX solutions.” Source: RevenueBase Database · checked Aug 30, 2026
4	Synacor	Partial evidence	London, United Kingdom	201-500	182 contacts →
	Partial evidence “Synacor is a cloud-based software and services company headquartered in Buffalo, New York with offices across the globe.” Source: RevenueBase Database · checked Aug 30, 2026
5	Luware	Strong evidence	London, United Kingdom	51-200	154 contacts →
	Strong evidence “Luware builds intelligent, cloud-native CX solutions that unlock the full potential of Microsoft Teams for enterprise communication.” Source: RevenueBase Database · checked Aug 30, 2026
6	NTT Ltd. Collaboration & CX	Indirect evidence	London, United Kingdom	10001+	120 contacts →
	Indirect evidence “The Collaboration and CX solutions offered by NTT Ltd.” Source: RevenueBase Database · checked Aug 30, 2026
7	Wavecrest	Indirect evidence	London, United Kingdom	51-200	92 contacts →
	Indirect evidence “Wavecrest is a global managed voice and messaging services company.” Source: RevenueBase Database · checked Aug 30, 2026
8	Sipcom	Indirect evidence	London, United Kingdom	501-1,000	84 contacts →
	Indirect evidence “Sipcom exists to make you the hero of your business narrative by turning complexity into clarity.” Source: RevenueBase Database · checked Aug 30, 2026
9	Microtalk	Strong evidence	London, United Kingdom	11-50	44 contacts →
	Strong evidence “Microtalk: Global Communications Made Simple For over 15 years, Microtalk has delivered reliable voice, messaging, and cloud communications to businesses worldwide.” Source: RevenueBase Database · checked Aug 30, 2026
10	Quickblox	Strong evidence	London, United Kingdom	11-50	31 contacts →
	Strong evidence “QuickBlox is a leading cloud communication platform helping businesses bring AI-driven chat, video, and automation into their digital products-quickly, securely, and at scale.” Source: RevenueBase Database · checked Aug 30, 2026
11	Marlin Communications	Partial evidence	London, United Kingdom	11-50	22 contacts →
	Partial evidence “Marlin Communications is a UK-based, single-source provider of business communications technology solutions that helps organisations improve customer experiences and optimise how…” Source: RevenueBase Database · checked Aug 30, 2026
12	Conversant Technology	Partial evidence	London, United Kingdom	11-50	17 contacts →
	Partial evidence “Conversant Technology empowers businesses with digital-first communication solutions, built on the strength of Microsoft Teams.” Source: RevenueBase Database · checked Aug 30, 2026
13	VTSL	Strong evidence	London, United Kingdom	11-50	15 contacts →
	Strong evidence “VTSL Ltd is a leading cloud communications company in the UK & Ireland.” Source: RevenueBase Database · checked Aug 30, 2026
14	The Technology Group	Partial evidence	London, United Kingdom	11-50	8 contacts →
	Partial evidence “The Technology Group are a managed communications provider, helping businesses and organisations to better communicate with their customers and teams, by embracing voice over IP…” Source: RevenueBase Database · checked Aug 30, 2026
15	Purpleuc	Partial evidence	London, United Kingdom	11-50	7 contacts →
	Partial evidence “PurpleUC specialises in hosted Cloud IP telephony and Internet connectivity.” Source: RevenueBase Database · checked Aug 30, 2026
16	Purify Technology LTD	Indirect evidence	London, United Kingdom	1-10	7 contacts →
	Indirect evidence “Purify helps you make the right technology choices to increase productivity and create confident teams that reach their full potential.” Source: RevenueBase Database · checked Aug 30, 2026
17	Holler Technology LTD	Partial evidence	London, United Kingdom	11-50	7 contacts →
	Partial evidence “At Holler we believe in the cloud but only when partnered with feet on the street to deliver the very best solutions and support.” Source: RevenueBase Database · checked Aug 30, 2026
18	APALO	Partial evidence	London, United Kingdom	1-10	7 contacts →
	Partial evidence “THE MOBILE FIRST COMMUNICATION PLATFORM WITH FMC & WebRTC Apalo takes smarter communications to the next level, combining a comprehensive set of collaboration tools and rich…” Source: RevenueBase Database · checked Aug 30, 2026
19	ZIAAS	Indirect evidence	London, United Kingdom	11-50	6 contacts →
	Indirect evidence “At ZiAAS, we're passionate about harnessing the power of technology to transform businesses and streamline operations.” Source: RevenueBase Database · checked Aug 30, 2026
20	Glemnet LTD	Strong evidence	London, United Kingdom	1-10	6 contacts →
	Strong evidence “Glemnet is part of Southern Communications Company (SCG Corporate), provider of telecoms, cloud communications and IT services to businesses of all sizes- from start ups through…” Source: RevenueBase Database · checked Aug 30, 2026
21	Moore Technology LTD	Partial evidence	London, United Kingdom	1-10	5 contacts →
	Partial evidence “We are specialists in cloud technology, our ethos is “Customer First”, our mission is to empower our customers with agile, cost effective, innovative technology, without long term…” Source: RevenueBase Database · checked Aug 30, 2026
22	Sipalto	Partial evidence	London, United Kingdom	11-50	4 contacts →
	Partial evidence “Sipalto is made up of remarkable individuals who pool their wealth of knowledge, understanding and expertise to deliver an incredible communications experience.” Source: RevenueBase Database · checked Aug 30, 2026
23	Voicelinx LTD	Indirect evidence	London, United Kingdom	1-10	4 contacts →
	Indirect evidence “Voicelinx are experts in VOIP telecoms.” Source: RevenueBase Database · checked Aug 30, 2026
24	Revolution Phones LTD	Indirect evidence	London, United Kingdom	1-10	2 contacts →
	Indirect evidence “Revolution Phones was established specifically to provide state-of-the art Internet-connected telephone systems.” Source: RevenueBase Database · checked Aug 30, 2026
25	Exponential-E Limited	Indirect evidence	London, United Kingdom	501-1,000	2 contacts →
	Indirect evidence Source: RevenueBase Database · checked Aug 30, 2026

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: cloud communications companies. 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 cloud communications companies.
Partial evidence: Its own public description names part of cloud communications companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name cloud communications companies. 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 69 cloud communications companies based in London, United Kingdom

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Cloud communications companies based in London, United Kingdom at a glance

As of Aug 30, 2026

36.4%Verified-email coverage

17.0%Mobile-number coverage

36.4Average contacts per company

11-50Median size (employees)

100.0%Largest-city concentration · London

Aug 30, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

10001+

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 cloud communications 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 London, United Kingdom whose own description of what they do matches “cloud communications 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 cloud communications 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 cloud communications companies, and records with no verified work email. Companies headquartered outside London 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, 914 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 August 30, 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.

Cloud communications companies by metro in the United Kingdom

Cloud communications companies in London69

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 cloud communications 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 cloud communications companies are there based in London, United Kingdom?

RevenueBase identified 69 cloud communications companies headquartered in London, United Kingdom as of August 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?

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

Which city has the most cloud communications companies?

London leads with 69 headquartered companies, followed by Manchester (6) and Poole (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 914 verified decision-maker contacts tracked across these 69 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on August 30, 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.