Company lists · Data refreshed September 2026

Top 25 Security testing companies based in the Netherlands

RevenueBase identified 145 security testing companies headquartered in the Netherlands as of September 2026 and tracks 1,234 professional contacts across them, including 305 with verified work emails and 68 with mobile numbers. Amsterdam is the largest hub.

This list covers security testing companies headquartered in the Netherlands, 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 6, 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 6, 2026 86% judged on-target in blind review
145Companies
1,234Contacts tracked
305Verified emails
68Mobile numbers
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The 25 largest security testing companies based in the Netherlands

Ranked by team size
Top 25 of 145 security testing companies based in the Netherlands, ranked by team size, largest first. Data refreshed Sep 6, 2026. RevenueBase Smart Search rates how each company's information relates to security testing 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceAmsterdam, NetherlandsHQ checked Sep 6, 202651-20060 contacts →

“Test your software, not your reputation!”

Source: company website · checked Sep 6, 2026
2Partial evidence3447gg, NetherlandsHQ checked Sep 6, 202611-5037 contacts →

“Surelock IT Security Services helpt organisatie inzicht te krijgen in de IT-kwetsbaarheden van hun organisatie.”

Source: company website · checked Sep 6, 2026
3Strong evidenceAmsterdam, NetherlandsHQ checked Sep 6, 202611-5034 contacts →

“Penetration Testing | Agile Security Testing | Red Teaming Securify is a cybersecurity company with a team of professional and passionate ethical hackers, secure coding experts…”

Source: company website · checked Sep 6, 2026
4Indirect evidenceUtrecht, NetherlandsHQ checked Sep 6, 202611-5028 contacts →

“Omdat IT van onschatbare waarde is om commerciële en maatschappelijke doelen te verwezenlijken zijn pogingen om onrechtmatige toegang tot uw informatie te krijgen helaas aan de…”

Source: company website · checked Sep 6, 2026
5Partial evidenceDelft, NetherlandsHQ checked Sep 6, 202611-5025 contacts →

“LBVD is een Delfts onderzoeks- en adviesbureau gespecialiseerd in digitale veiligheid, cybersecurity (ICT-security) en informatiebeveiliging, met 20+ jaar ervaring.”

Source: company website · checked Sep 6, 2026
6Partial evidenceXj, NetherlandsHQ checked Sep 6, 202651-20023 contacts →

“Riscure is an independent security laboratory founded in 2001 with customers in North America, Europe and Asia.”

Source: company website · checked Sep 6, 2026
7Indirect evidenceRotterdam, NetherlandsHQ checked Sep 6, 202611-5023 contacts →

“ThreadStone is uw toonaangevende specialist op het gebied van cybersecurity.”

Source: company website · checked Sep 6, 2026
8Strong evidenceLeiden, NetherlandsHQ checked Sep 6, 202611-5018 contacts →

“DongIT is an independent web security and web development company specializing in penetration testing, secure software development, and custom-built web applications.”

Source: company website · checked Sep 6, 2026
9Indirect evidenceLeiderdorp, NetherlandsHQ checked Sep 6, 202611-5016 contacts →

“REQON is gespecialiseerd in het uitvoeren van technische beveiligingsonderzoeken in de vorm van (maatwerk) penetratietesten en exposure onderzoeken.”

Source: company website · checked Sep 6, 2026
10Indirect evidenceUtrecht, NetherlandsHQ checked Sep 6, 202611-5015 contacts →

“At Cyber Seals, we believe in a digital world where you can work, innovate, and grow securely.”

Source: company website · checked Sep 6, 2026
11Partial evidenceLopik, NetherlandsHQ checked Sep 6, 202611-5014 contacts →

“Bij HOB ICT Security werken we dagelijks aan het versterken van de weerbaarheid van middelgrote en grote organisaties tegen alle vormen van cyberdreigingen.”

Source: company website · checked Sep 6, 2026
12Partial evidenceRotterdam, NetherlandsHQ checked Sep 6, 202611-5014 contacts →

“Base is a niche consultancy & managed security solutions provider, offering services enabling organizations, and professionals, to build knowledge & capabilities in information…”

Source: company website · checked Sep 6, 2026
13Partial evidenceAlkmaar, NetherlandsHQ checked Sep 6, 20261-1012 contacts →

“Specialists from Sirius Security have all the skills to help enterprise organisations to secure their IT environment.”

Source: company website · checked Sep 6, 2026
14Indirect evidenceEindhoven, NetherlandsHQ checked Sep 6, 202611-5011 contacts →

“We are eager to use our expertise to create a digital world where information is secure and websites are reliable.”

Source: company website · checked Sep 6, 2026
15Partial evidenceAlmere, NetherlandsHQ checked Sep 6, 202611-5011 contacts →

“Even when your security is well underpinned, it remains important to remain alert to possible vulnerabilities, to the system's alerting and response capabilities and to the…”

Source: company website · checked Sep 6, 2026
16Partial evidenceAmsterdam, NetherlandsHQ checked Sep 6, 20261-1011 contacts →

“Sekurno is a cybersecurity company that provides security services beyond mere compliance.”

Source: company website · checked Sep 6, 2026
17Partial evidenceCapelle Aan Den Ijssel, NetherlandsHQ checked Sep 6, 20261-1011 contacts →

“Cyber7 Cyber Security Consultancy”

Source: company website · checked Sep 6, 2026
18Partial evidenceAbcoude, NetherlandsHQ checked Sep 6, 202611-5010 contacts →

“Cyber Security Challengers (CSC) is uw onafhankelijke cybersecurity expert en dienstverlener.”

Source: company website · checked Sep 6, 2026
19Indirect evidenceBleskensgraaf, NetherlandsHQ checked Sep 6, 20261-1010 contacts →

“Cyber Cloud is een jong, ambitieus en innovatief bedrijf, gespecialiseerd in het uitvoeren van technische testen met als doel kwetsbaarheden in uw (web/mobiele)applicaties…”

Source: company website · checked Sep 6, 2026
20Indirect evidenceRoelofarendsveen, NetherlandsHQ checked Sep 6, 20261-1010 contacts →

“Hoe vatbaar is jouw organisatie voor hacks?”

Source: company website · checked Sep 6, 2026
21Indirect evidenceUtrecht, NetherlandsHQ checked Sep 6, 202611-509 contacts →

“Onvio is dé specialist in het uitvoeren van Pentesten.”

Source: company website · checked Sep 6, 2026
22Indirect evidenceIjsselstein, NetherlandsHQ checked Sep 6, 202651-2009 contacts →

“Qualityhouse heet sinds 1 januari 2014 Centric.”

Source: company website · checked Sep 6, 2026
23Indirect evidenceZoetermeer, NetherlandsHQ checked Sep 6, 20261-109 contacts →

“Zoeken naar verbinding, en het bieden van totaaloplossingen, dat is waar wij continu mee bezig zijn.”

Source: company website · checked Sep 6, 2026
24Partial evidenceAmsterdam, NetherlandsHQ checked Sep 6, 202611-508 contacts →

“WebSec is an all-in-one security company.”

Source: company website · checked Sep 6, 2026
25Indirect evidenceZevenbergen, NetherlandsHQ checked Sep 6, 202611-507 contacts →

“With Attic, the hacking experts from Zolder provide organizations with high-end cybersecurity operations.”

Source: company website · checked Sep 6, 2026

Showing 25 of 145 security testing companies based in the Netherlands

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Security testing companies based in the Netherlands at a glance

As of Sep 6, 2026
24.7%Verified-email coverage
5.5%Mobile-number coverage
8.5Average contacts per company
1-10Median size (employees)
16.6%Largest-city concentration · Amsterdam
Sep 6, 2026Page data refreshed

Companies by employee count

1-10
94
11-50
42
51-200
8
201-500
1

Freshness & accuracy

How recently the business emails on this list were verified

Email last verified

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 security testing 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 the Netherlands whose own description of what they do matches “security testing 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 security testing 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 security testing companies, and records with no verified work email. Companies headquartered outside Netherlands 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, 305 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 6, 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 security testing 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 security testing companies are there based in the Netherlands?

RevenueBase identified 145 security testing companies headquartered in the Netherlands 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?

Spritecloud, headquartered in Amsterdam, tops this list with the largest team on record.

Which city has the most security testing companies?

Amsterdam leads with 24 headquartered companies, followed by Utrecht (5) and Eindhoven (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 305 verified decision-maker contacts tracked across these 145 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 6, 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.