Company lists · Data refreshed September 2026

Top 25 App security companies based in London, United Kingdom

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

Compiled by the RevenueBase Data Team Data refreshed Sep 24, 2026 98 companies tracked

RevenueBase identified 98 app security companies headquartered in London, United Kingdom as of September 2026 and tracks 1,148 professional contacts across them, including 279 with verified work emails and 101 with mobile numbers. Across the United Kingdom, London is the largest hub for this category.

This list covers app security 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 September 24, 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 24, 2026 86% judged on-target in blind review

98Companies

1,148Contacts tracked

279Verified emails

101Mobile numbers

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The 25 largest app security companies based in London, United Kingdom

Ranked by team size

Top 25 of 98 app security companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 24, 2026. RevenueBase Smart Search rates how each company's information relates to app security 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	Titania LTD	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	88 contacts →
	Partial evidence “Dedicated to securing the networks society depends on.” Source: RevenueBase Database · checked Sep 24, 2026
2	White HAT An Epam Company	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	77 contacts →
	Partial evidence “White Hat, part of the EPAM group, is an award-winning cyber intelligence and offensive security company that leverages an attacker’s perspective to shape innovative, proactive…” Source: RevenueBase Database · checked Sep 24, 2026
3	Intruder	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	61 contacts →
	Partial evidence “Intruder's continuous exposure management platform helps security, IT, and engineering teams stop breaches before they start.” Source: RevenueBase Database · checked Sep 24, 2026
4	Secureflag	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	57 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 24, 2026
5	Riversafe	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	57 contacts →
	Partial evidence “We deliver services in Cybersecurity, Application Security and DevOps and are trusted by some of the world’s leading brands to maximise the value of their security investments and…” Source: RevenueBase Database · checked Sep 24, 2026
6	Redhunt Labs	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	36 contacts →
	Partial evidence “RedHunt Labs is a research-driven cybersecurity company delivering Continuous Threat Exposure Management (CTEM), PTaaS, and AI Exposure Security.” Source: RevenueBase Database · checked Sep 24, 2026
7	snapsec.co	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	30 contacts →
	Partial evidence “SnapSec is a cybersecurity company specializing in centralized application security operations.” Source: RevenueBase Database · checked Sep 24, 2026
8	Ssl247 A Sectigo Company	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	24 contacts →
	Partial evidence “SSL247 (A Sectigo Company) has nearly 20 years of security consulting experience operating in 18 different markets globally.” Source: RevenueBase Database · checked Sep 24, 2026
9	Secure Purple	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	20 contacts →
	Partial evidence “Secure Purple is a leading cyber security and digital safety firm that provides innovative solutions and services to help organisations and individuals stay protected in the…” Source: RevenueBase Database · checked Sep 24, 2026
10	CST Limited Computer Security Technology	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	17 contacts →
	Partial evidence “We are a London based specialist supplier of cyber defence solution and information security services.” Source: RevenueBase Database · checked Sep 24, 2026
11	Vulnhero	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	16 contacts →
	Partial evidence “VulnHero is an AI-driven continuous full-stack offensive security platform that helps teams see what scanners miss and focus on exploitable risk first.” Source: RevenueBase Database · checked Sep 24, 2026
12	Datasixth Consulting	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	15 contacts →
	Indirect evidence “Who We Are DataSixth delivers Cybersecurity Intelligence.” Source: RevenueBase Database · checked Sep 24, 2026
13	Eh1-Infotech Cybersecurity	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	15 contacts →
	Indirect evidence “is an ISO 9001:2015 and ISO/IEC 27001:2022 certified, DPIIT-recognized cybersecurity company delivering structured External Vulnerability Assessment & Penetration Testing (VAPT)…” Source: RevenueBase Database · checked Sep 24, 2026
14	CYTAL	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	11 contacts →
	Partial evidence “CyTAL exists to help developers, manufacturers and their customers to improve the security and resilience of products and systems.” Source: RevenueBase Database · checked Sep 24, 2026
15	Disclosure Cybersecurity	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	11 contacts →
	Partial evidence “Disclosure Cybersecurity Ltd is a specialist cyber security company, formed by professionals with extensive experience and wide exposure in the cyber security market.” Source: RevenueBase Database · checked Sep 24, 2026
16	PC Power International LTD	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	10 contacts →
	Partial evidence “PC POWER INTERNATIONAL LTD is a computer & network security company based in the City, London, United Kingdom.” Source: RevenueBase Database · checked Sep 24, 2026
17	Pentiq	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	10 contacts →
	Partial evidence “We are a UK-based Cyber Security company offering a comprehensive portfolio specialising in innovative solutions for Penetration Testing, Training, Compliance, Consulting, and…” Source: RevenueBase Database · checked Sep 24, 2026
18	Validato	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	10 contacts →
	Indirect evidence “Validato helps organisations continuously validate and strengthen their cybersecurity controls using safe-to-use, production-ready Breach and Attack Simulation (BAS).” Source: RevenueBase Database · checked Sep 24, 2026
19	Appsecco	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	6 contacts →
	Indirect evidence “Appsecco Inc.” Source: RevenueBase Database · checked Sep 24, 2026
20	Fortbridge	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	5 contacts →
	Partial evidence “Every engagement led by consultants with 10-20 years of offensive security experience.” Source: RevenueBase Database · checked Sep 24, 2026
21	Laneden LTD	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	4 contacts →
	Partial evidence “We specialise in helping organisations identify security concerns and quantify the risks you may have across your assets, using Penetration Testing, Threat Simulation and…” Source: RevenueBase Database · checked Sep 24, 2026
22	Cybersanctus	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	4 contacts →
	Partial evidence “At CyberSanctus, we specialize in offensive security and penetration testing services designed to identify real-world risks before attackers do.” Source: RevenueBase Database · checked Sep 24, 2026
23	Grove Group	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	3 contacts →
	Indirect evidence “Grove unlocks business success by defending our customers with the most advanced cybersecurity solutions in the market place today.” Source: RevenueBase Database · checked Sep 24, 2026
24	Illume	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	3 contacts →
	Partial evidence “Illume are a UK-based cyber security specialist helping organisations identify risk, stop threats, and stay secure.” Source: RevenueBase Database · checked Sep 24, 2026
25	Zeroday Co., LTD	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	3 contacts →
	Partial evidence “Zeroday Co, Ltd is a company focusing on developing and delivering state-of-art application security testing tools/platforms.” Source: RevenueBase Database · checked Sep 24, 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: app security 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 app security companies.
Partial evidence: Its own public description names part of app security companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name app security 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 98 app security companies based in London, United Kingdom

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App security companies based in London, United Kingdom at a glance

As of Sep 24, 2026

24.3%Verified-email coverage

8.8%Mobile-number coverage

11.7Average contacts per company

1-10Median size (employees)

Sep 24, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

Freshness & accuracy

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

Email last verified

Median 27.0d

2000–30

7231–60

261–90

190–180

4180+

Company record updated

Median 87.0d

00–30

16331–60

55061–90

37490–180

61180+

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 app security 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 “app security 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 app security 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 app security 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, 279 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 24, 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 app security 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 app security companies are there based in London, United Kingdom?

RevenueBase identified 98 app security companies headquartered in London, 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?

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

Which city in the United Kingdom has the most app security companies?

London leads the United Kingdom with 45 headquartered companies, followed by Manchester (6) and Leeds (4).

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 279 verified decision-maker contacts tracked across these 98 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 24, 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.