Company lists · Data refreshed October 2026

Top 18 International calling software companies based in London, United Kingdom

RevenueBase identified 54 company matches for international calling software companies associated with London, United Kingdom as of October 2026 and tracks 1,001 professional contacts across them, including 193 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers company matches for international calling software companies associated with London, United Kingdom, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed October 19, 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 RevenueBase SmartSearch · Exact Recorded Oct 19, 2026 How this list was built
54Companies
1,001Contacts tracked
193Verified emails
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The 18 largest international calling software companies based in London, United Kingdom

Ranked by team size
Top 18 of 54 company matches for international calling software companies based in London, United Kingdom, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Oct 19, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#CompanyRevenueBase SmartSearchHeadquartersEmployeesContacts
1Exact matchLondon, United KingdomHQ recorded Oct 19, 202651-200161 contacts →

Exact match

“bOnline is UK’s leading provider of VoIP services for micro and small businesses.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
2Exact matchLondon, United KingdomHQ recorded Oct 19, 202651-20090 contacts →

Exact match

“Wavecrest is a global managed voice and messaging services company.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
3Exact matchLondon, United KingdomHQ recorded Oct 19, 202651-20089 contacts →

Exact match

“BlaBla Connect is an international calling app, available for IOS and Android users.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
4Exact matchLondon, United KingdomHQ recorded Oct 19, 202651-20082 contacts →

Exact match

“With a broad experience in the industry, Speedflow is in the best position to provide you with products and services proven by time to be effective.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
5Exact matchLondon, United KingdomHQ recorded Oct 19, 2026501-1,00080 contacts →

Exact match

“Sipcom exists to make you the hero of your business narrative by turning complexity into clarity.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
6Exact matchLondon, United KingdomHQ recorded Oct 19, 202651-20070 contacts →

Exact match

“Telappliant is an award-winning VoIP and cloud communications provider.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
7Exact matchLondon, United KingdomHQ recorded Oct 19, 202611-5045 contacts →

Exact match

“Microtalk: Wholesale SMS & Carrier-Grade Connectivity Simplified For over 15 years, Microtalk has empowered businesses globally with reliable voice, messaging, and cloud…”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
8Exact matchLondon, United KingdomHQ recorded Oct 19, 202611-5013 contacts →

Exact match

“VTSL Ltd is a leading cloud communications company in the UK & Ireland.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
9Exact matchLondon, United KingdomHQ recorded Oct 19, 20261-1011 contacts →

Exact match

“We connect millions of telephone calls for businesses each year, with our modern cloud technology and easy to use platforms.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
10Exact matchLondon, United KingdomHQ recorded Oct 19, 202651-20010 contacts →

Exact match

“DaoTec Ltd is a global leader in the fields of telecommunication, multimedia and software engineering delivering unique communication solutions to customers globally.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
11Exact matchLondon, United KingdomHQ recorded Oct 19, 202611-509 contacts →

Exact match

“Invomo’s hosted applications and services can transform phone-based communications with an organisation’s customers - whether landline or mobile, inbound and outbound.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
12Exact matchLondon, United KingdomHQ recorded Oct 19, 202611-508 contacts →

Exact match

“At ZiAAS, we're passionate about harnessing the power of technology to transform businesses and streamline operations.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
13Exact matchLondon, United KingdomHQ recorded Oct 19, 20261-107 contacts →

Exact match

“Telecommunications Company”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
14Exact matchLondon, United KingdomHQ recorded Oct 19, 20261-106 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
15Exact matchLondon, United KingdomHQ recorded Oct 19, 20261-105 contacts →

Exact match

“Voicelinx are experts in VOIP telecoms.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
16Exact matchLondon, United KingdomHQ recorded Oct 19, 20261-102 contacts →

Exact match

“Revolution Phones was established specifically to provide state-of-the art Internet-connected telephone systems.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
17Exact matchLondon, United KingdomHQ recorded Oct 19, 202611-502 contacts →

Exact match

“simplecall offers a low-cost international calling alternative to calling cards.”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase
18Exact matchLondon, United KingdomHQ recorded Oct 19, 20261-101 contacts →

Exact match

“Ansr is a cloud based VoIP telephony and messaging infrastructure web service that enables both VoIP communications as well as developers and web programmers to integrate voice…”

Recorded in the RevenueBase company graph · Oct 19, 2026 · View company records in RevenueBase

Showing 18 of 54 international calling software companies based in London, United Kingdom

See the full list, filter by size, metro and specialty, and access 193 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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International calling software companies based in London, United Kingdom at a glance

As of Oct 19, 2026
19.3%Verified-email coverage
18.5Average contacts per company
11-50Median size (employees)
Oct 19, 2026Page data refreshed

Companies by employee count

1-10
22
11-50
19
51-200
10
501-1,000
1
10001+
1

Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 54 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

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
Company records associated with London, United Kingdom whose business descriptions match “international calling software companies” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch
Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview
The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality
RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
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 displayed company carries at least one verified work email. RevenueBase tracks 193 professional contacts with verified work emails across the full matched dataset. 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 October 19, 2026. Lists refresh periodically as the graph is re-checked.
Record context
Company records and descriptions can change. Check the company's website for its current services and locations.

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “international calling software companies”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many international calling software companies are there based in London, United Kingdom?

RevenueBase identified 54 company matches for international calling software companies associated with London, United Kingdom as of October 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Bonline tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city in the United Kingdom has the most international calling software companies?

London leads the United Kingdom with 54 company records, followed by Birmingham (5) and Bolton (4).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 193 professional contacts with verified work emails tracked across these 54 companies; direct dials are available where recorded.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on October 19, 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 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.