Company lists · Data refreshed September 2026

Top 25 Application security products and services providers based in the United Kingdom

RevenueBase identified 93 application security products and services providers headquartered in the United Kingdom as of September 2026 and tracks 1,279 professional contacts across them, including 409 with verified work emails. London is the largest hub.

This list covers application security products and services providers 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 21, 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 21, 2026 86% judged on-target in blind review
93Companies
1,279Contacts tracked
409Verified emails
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest application security products and services providers based in the United Kingdom

Ranked by team size
Top 25 of 93 application security products and services providers based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to application security products and services providers: 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 21, 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 21, 2026
2Partial evidenceLeeds, United KingdomHQ checked Sep 21, 202651-20099 contacts →

Partial evidence

“AppCheck is a Complete Enterprise Security Testing Solution that provides up to the minute vulnerability coverage for your entire estate.”

Source: RevenueBase Database · checked Sep 21, 2026
3Partial evidenceLondon, United KingdomHQ checked Sep 21, 202651-20061 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 21, 2026
4Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202651-20057 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 21, 2026
5Strong evidenceLondon, United KingdomHQ checked Sep 21, 202611-5057 contacts →

Strong 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 21, 2026
6Indirect evidenceManchester, United KingdomHQ checked Sep 21, 202611-5036 contacts →

Indirect evidence

“Secarma exists to keep the world safe.”

Source: RevenueBase Database · checked Sep 21, 2026
7Strong evidenceLondon, United KingdomHQ checked Sep 21, 20261-1030 contacts →

Strong evidence

“SnapSec is a cybersecurity company specializing in centralized application security operations.”

Source: RevenueBase Database · checked Sep 21, 2026
8Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202611-5028 contacts →

Indirect evidence

“Licel is a mobile channel protection company.”

Source: RevenueBase Database · checked Sep 21, 2026
9Partial evidenceRoyston, United KingdomHQ checked Sep 21, 202611-5025 contacts →

Partial evidence

“Critical Endpoint Security | Unified Endpoint Management | Business Continuity Assessment Services | Resource Support and Consultancy | Powered by Tanium | Trend Micro Partner |…”

Source: RevenueBase Database · checked Sep 21, 2026
10Partial evidenceLondon, United KingdomHQ checked Sep 21, 202651-20024 contacts →

Partial evidence

“Nanjgel Solutions is focused on delivering the best IT security for businesses.”

Source: RevenueBase Database · checked Sep 21, 2026
11Indirect evidenceLeeds, United KingdomHQ checked Sep 21, 202611-5019 contacts →

Indirect evidence

“Halo I.S is not just another cybersecurity organization based in the UK; we're a testament to evolution and client-centric innovation.”

Source: RevenueBase Database · checked Sep 21, 2026
12Partial evidenceCheltenham, United KingdomHQ checked Sep 21, 202611-5014 contacts →

Partial evidence

“CloudSecure delivers secure software and cloud systems for security-critical environments.”

Source: RevenueBase Database · checked Sep 21, 2026
13Indirect evidenceBath, United KingdomHQ checked Sep 21, 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 21, 2026
14Partial evidenceMarlow Bucks, United KingdomHQ checked Sep 21, 20261-109 contacts →

Partial evidence

“Formed in 2010, Security Software Solutions Ltd (S3 Ltd) has become a recognised force in Enterprise Security Solutions in Europe.”

Source: RevenueBase Database · checked Sep 21, 2026
15Indirect evidenceManchester, United KingdomHQ checked Sep 21, 202611-508 contacts →

Indirect evidence

“Cytix is the AppSec layer that focuses testing where it matters.”

Source: RevenueBase Database · checked Sep 21, 2026
16Indirect evidenceLondon, United KingdomHQ checked Sep 21, 20261-106 contacts →

Indirect evidence

“Appsecco Inc.”

Source: RevenueBase Database · checked Sep 21, 2026
17Indirect evidenceCranfield, United KingdomHQ checked Sep 21, 202611-506 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
18Partial evidenceWhiteley, United KingdomHQ checked Sep 21, 20261-106 contacts →

Partial evidence

“We provide market-leading cybersecurity products to protect your mobile devices and computers from malicious attacks, identity theft and fraud.”

Source: RevenueBase Database · checked Sep 21, 2026
19Partial evidenceLondon, United KingdomHQ checked Sep 21, 20261-104 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 21, 2026
20Partial evidenceLongford, United KingdomHQ checked Sep 21, 202611-503 contacts →

Partial evidence

“CyberSafe is the original commercial provider of Kerberos-based security solutions, with over 20 years' experience, and focused on providing innovative security solutions for SAP…”

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

Partial 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 21, 2026
22Strong evidenceLondon, United KingdomHQ checked Sep 21, 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 21, 2026
23Partial evidenceHaslemere, United KingdomHQ checked Sep 21, 20261-103 contacts →

Partial evidence

“AVm has many years experience and expertise in IT security.”

Source: RevenueBase Database · checked Sep 21, 2026
24Partial evidenceLondon, United KingdomHQ checked Sep 21, 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 21, 2026
25Partial evidenceLondon, United KingdomHQ checked Sep 21, 20261-103 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 93 application security products and services providers based in the United Kingdom

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 409 reachable decision-makers.

Free signup · no credit card

View the full list →

Application security products and services providers based in the United Kingdom at a glance

As of Sep 21, 2026
32.0%Verified-email coverage
13.8Average contacts per company
1-10Median size (employees)
47.3%Largest-city concentration · London
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
53
11-50
28
51-200
9
201-500
1
10001+
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 93 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 application security products and services providers, 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 “application security products and services providers”. 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 application security products and services providers), 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 application security products and services providers, 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, 409 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 21, 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.

Application security products and services providers by metro

  • Application security products and services providers in London44

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 application security products and services providers, 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 application security products and services providers are there based in the United Kingdom?

RevenueBase identified 93 application security products and services providers 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 application security products and services providers?

London leads with 44 headquartered companies, followed by Leeds (5) and Manchester (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 409 verified decision-maker contacts tracked across these 93 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 21, 2026.

Ready to reach these companies? Verified emails and direct dials for all 93 application security products and services providers based in the United Kingdom. Start with a free account, no credit card.

Download this list →

Related lists

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.