Company lists · Data refreshed September 2026
Top 25 Api security assessment services based in the United Kingdom
RevenueBase identified 71 api security assessment services headquartered in the United Kingdom as of September 2026 and tracks 1,430 professional contacts across them, including 182 with verified work emails. London is the largest hub.
This list covers api security assessment services 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 27, 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.
The 25 largest api security assessment services based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 99 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 27, 2026Thanks. The Data Team will review it. | |||||
| 2 | 19 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 27, 2026Thanks. The Data Team will review it. | |||||
| 3 | 15 contacts → | ||||
Partial 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 27, 2026Thanks. The Data Team will review it. | |||||
| 4 | 14 contacts → | ||||
Partial evidence “Demand more from your AI & Data Security partner.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 5 | 11 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 27, 2026Thanks. The Data Team will review it. | |||||
| 6 | 7 contacts → | ||||
Partial evidence “RM Information Security are a specialist penetration testing and information security consultancy based in the north of England.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 7 | 6 contacts → | ||||
Indirect evidence “Appsecco Inc.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 8 | 6 contacts → | ||||
Indirect evidence “Secure Debug: Your Full-Spectrum Cybersecurity Guardian!” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 9 | 6 contacts → | ||||
Indirect evidence “NGS Secure is now NCC Group NCC Group is a leading global information assurance firm, providing freedom from doubt that all critical material is available, protected, and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 10 | 5 contacts → | ||||
Partial evidence “Every engagement led by consultants with 10-20 years of offensive security experience.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 11 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 12 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 13 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 14 | 3 contacts → | ||||
Strong evidence “Sentrium is a bespoke cyber security consultancy, powered by extensive business and technical expertise that provides you with the assessment and advisory services you need to…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 15 | 3 contacts → | ||||
Partial evidence “Founded in London in 2019, Pyramid Ledger is a leading cybersecurity firm dedicated to enhancing digital security with comprehensive and bespoke solutions.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 16 | 3 contacts → | ||||
Partial evidence “At Securityium, we're dedicated to transforming the way you experience security testing for your business.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 17 | 3 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 27, 2026Thanks. The Data Team will review it. | |||||
| 18 | 2 contacts → | ||||
Indirect evidence “We believe that effective cybersecurity is within the reach of every organisation.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 19 | 2 contacts → | ||||
Indirect evidence “We are a team of well-trained and experienced cybersecurity professionals that offer a multitude of testing, such as: Web application, Infrastructure penetration, Android…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 20 | 2 contacts → | ||||
Strong evidence “Anchorsec advances cybersecurity by providing comprehensive and insightful security assessments.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 21 | 2 contacts → | ||||
Partial evidence “We are a selected team of UK based security professionals.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 22 | 2 contacts → | ||||
Indirect evidence “Dhound is a cybersecurity company providing web application penetration testing, focused on manual approach and comprehensive delivery, helping IT companies be secure and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 23 | 2 contacts → | ||||
Indirect evidence “Who we are.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 24 | 2 contacts → | ||||
Partial evidence “Secure Delivery is an application security consulting and training company helping regulated organisations securely deliver software systems at pace and scale.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 25 | 2 contacts → | ||||
Partial evidence “Securebytes® Solutions LTD is a UK-based, trusted cyber security partner, combining CREST-certified penetration testing with IASME-accredited certification services.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
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: api security assessment services. 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 api security assessment services.
- Partial evidence
- Its own public description names part of api security assessment services, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name api security assessment services. 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 71 api security assessment services based in the United Kingdom
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Api security assessment services based in the United Kingdom at a glance
As of Sep 27, 2026Companies by employee count
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 71 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 api security assessment services, 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 “api security assessment services”. 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 api security assessment services), 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 api security assessment services, 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, 182 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 27, 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.
Api security assessment services by metro
- Api security assessment services in London32
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 api security assessment services, 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 api security assessment services are there based in the United Kingdom?
RevenueBase identified 71 api security assessment services 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?
Appcheck LTD, headquartered in Leeds, tops this list with the largest team on record.
Which city has the most api security assessment services?
London leads with 32 headquartered companies, followed by Leeds (4) 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 182 verified decision-maker contacts tracked across these 71 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 27, 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.
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