Company lists · Data refreshed September 2026

Top 25 Penetration testing tool vendors based in the United Kingdom

RevenueBase identified 79 penetration testing tool vendors headquartered in the United Kingdom as of September 2026 and tracks 890 professional contacts across them, including 243 with verified work emails. London is the largest hub.

This list covers penetration testing tool vendors 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 20, 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 20, 2026 86% judged on-target in blind review
79Companies
890Contacts tracked
243Verified emails
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The 25 largest penetration testing tool vendors based in the United Kingdom

Ranked by team size
Top 25 of 79 penetration testing tool vendors based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to penetration testing tool vendors: 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
1Strong evidenceKnutsford, United KingdomHQ checked Sep 20, 202651-200267 contacts →

Strong evidence

“PortSwigger is a global leader in the creation of software tools for security testing of web applications.”

Source: RevenueBase Database · checked Sep 20, 2026
2Partial evidenceBasingstoke, United KingdomHQ checked Sep 20, 202651-20049 contacts →

Partial evidence

“Human-Led Continuous Testing.”

Source: RevenueBase Database · checked Sep 20, 2026
3Strong evidenceBristol, United KingdomHQ checked Sep 20, 202651-20039 contacts →

Strong evidence

“OnSecurity offers CREST-accredited AI Augmented Penetration Testing, all whilst harnessing technology to simplify the management and delivery of pentesting.”

Source: RevenueBase Database · checked Sep 20, 2026
4Indirect evidenceCambridge, United KingdomHQ checked Sep 20, 202611-5034 contacts →

Indirect evidence

“Pentesting Exams by Pentesting Experts.”

Source: RevenueBase Database · checked Sep 20, 2026
5Indirect evidenceLondon, United KingdomHQ checked Sep 20, 20261,001-5,00033 contacts →

Indirect evidence

“NotSoSecure Training, part of Claranet Cyber Security.”

Source: RevenueBase Database · checked Sep 20, 2026
6Strong evidenceLondon, United KingdomHQ checked Sep 20, 202611-5015 contacts →

Strong 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 20, 2026
7Indirect evidenceHolborn, United KingdomHQ checked Sep 20, 20261-1013 contacts →

Indirect evidence

“Laburity: Cyber Security Research and Services Company.”

Source: RevenueBase Database · checked Sep 20, 2026
8Strong evidenceMilton Keynes, United KingdomHQ checked Sep 20, 202611-5012 contacts →

Strong evidence

“We offer specialist CREST & CHECK Approved Penetration Testing services in order to secure our clients most critical assets.”

Source: RevenueBase Database · checked Sep 20, 2026
9Indirect evidenceBath, United KingdomHQ checked Sep 20, 202611-5011 contacts →

Indirect evidence

“At Mobius Binary we care about your reputation and the loss that could result from violating your digital boundaries.”

Source: RevenueBase Database · checked Sep 20, 2026
10Strong evidenceLondon, United KingdomHQ checked Sep 20, 202611-508 contacts →

Strong evidence

“We provide a wide range of Penetration Testing Services: External & Internal Network Pentest, Application Pentest and Social Engineering Attacks.”

Source: RevenueBase Database · checked Sep 20, 2026
11Strong evidenceManchester, United KingdomHQ checked Sep 20, 20261-107 contacts →

Strong evidence

“RM Information Security are a specialist penetration testing and information security consultancy based in the north of England.”

Source: RevenueBase Database · checked Sep 20, 2026
12Indirect evidenceBirmingham, United KingdomHQ checked Sep 20, 202611-506 contacts →

Indirect evidence

“Cyndicate Labs are a UK based Cyber Security consultancy.”

Source: RevenueBase Database · checked Sep 20, 2026
13Indirect evidenceCranfield, United KingdomHQ checked Sep 20, 202611-506 contacts →

Indirect evidence

“Secure Debug: Your Full-Spectrum Cybersecurity Guardian!”

Source: RevenueBase Database · checked Sep 20, 2026
14Strong evidenceBlackpool, United KingdomHQ checked Sep 20, 20261-105 contacts →

Strong evidence

“Akimbo Core are a Cybersecurity company offering Penetration Testing, Cybersecurity Training, and Consultancy.”

Source: RevenueBase Database · checked Sep 20, 2026
15Partial evidenceBrighton, United KingdomHQ checked Sep 20, 202611-505 contacts →

Partial evidence

“Informer's External Attack Surface Management (EASM) and Pen Testing platform help CISOs, CTOs and IT teams map external assets and identify vulnerabilities in real time so they…”

Source: RevenueBase Database · checked Sep 20, 2026
16Indirect evidenceLondon, United KingdomHQ checked Sep 20, 20261-105 contacts →

Indirect evidence

“Every engagement led by consultants with 10-20 years of offensive security experience.”

Source: RevenueBase Database · checked Sep 20, 2026
17Strong evidenceGaerwen, United KingdomHQ checked Sep 20, 20261-104 contacts →

Strong evidence

“Your Trusted CREST Certified Penetration Testing Partner.”

Source: RevenueBase Database · checked Sep 20, 2026
18Strong evidenceLondon, United KingdomHQ checked Sep 20, 202611-504 contacts →

Strong 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 20, 2026
19Strong evidenceMaidstone, United KingdomHQ checked Sep 20, 20261-104 contacts →

Strong evidence

“After spending over a decade working in the cyber security industry, I noticed that many organisations that once specialised in penetration testing were being bought out or had…”

Source: RevenueBase Database · checked Sep 20, 2026
20Strong evidenceStevenage, United KingdomHQ checked Sep 20, 202611-503 contacts →

Strong evidence

“Armadillo Sec Ltd, a Chess Group company, are a specialist cyber security testing organisation, offering expert penetration testing, simulated attack testing, vulnerability…”

Source: RevenueBase Database · checked Sep 20, 2026
21Indirect evidenceLeeds, United KingdomHQ checked Sep 20, 20261-103 contacts →

Indirect evidence

“CodeGrazer is the newly formed pentest firm based in Leeds, UK, offering security services to protect private companies internal infrastructure and web services with quick…”

Source: RevenueBase Database · checked Sep 20, 2026
22Strong evidenceLondon, United KingdomHQ checked Sep 20, 202611-503 contacts →

Strong 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 20, 2026
23Partial evidenceLondon, United KingdomHQ checked Sep 20, 20261-103 contacts →

Partial evidence

“At Securityium, we're dedicated to transforming the way you experience security testing for your business.”

Source: RevenueBase Database · checked Sep 20, 2026
24Indirect evidenceLondon, United KingdomHQ checked Sep 20, 20261-103 contacts →

Indirect evidence

“CyberLegion is a UK/EU-based cybersecurity company helping organizations build, test and operate secure digital products.”

Source: RevenueBase Database · checked Sep 20, 2026
25Indirect evidenceCambridge, United KingdomHQ checked Sep 20, 202611-502 contacts →

Indirect evidence

“We believe that effective cybersecurity is within the reach of every organisation.”

Source: RevenueBase Database · checked Sep 20, 2026

Showing 25 of 79 penetration testing tool vendors based in the United Kingdom

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Penetration testing tool vendors based in the United Kingdom at a glance

As of Sep 20, 2026
27.3%Verified-email coverage
11.3Average contacts per company
1-10Median size (employees)
46.8%Largest-city concentration · London
Sep 20, 2026Page data refreshed

Companies by employee count

1-10
51
11-50
22
51-200
4
201-500
1
1,001-5,000
1

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 79 companies.

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 penetration testing tool vendors, 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 “penetration testing tool vendors”. 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 penetration testing tool vendors), 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 penetration testing tool vendors, 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, 243 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 20, 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.

Penetration testing tool vendors by metro

  • Penetration testing tool vendors in London37

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 penetration testing tool vendors, 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 penetration testing tool vendors are there based in the United Kingdom?

RevenueBase identified 79 penetration testing tool vendors 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?

Portswigger, headquartered in United Kingdom, tops this list with the largest team on record.

Which city has the most penetration testing tool vendors?

London leads with 37 headquartered companies, followed by Manchester (3) and Brighton (2).

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 243 verified decision-maker contacts tracked across these 79 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 20, 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.