A UK cybersecurity start-up that helps small security teams find and fix weaknesses in their systems.
Intruder is a cybersecurity company that helps businesses find and fix weak spots in their computer systems before criminals do. Its platform scans what a company has exposed on the internet, checks cloud set-ups and ranks problems so teams fix the most important ones first. Its tagline for the work is that it makes it easier to not get hacked.
Intruder was founded in 2015 by Chris Wallis, who is still its chief executive. Wallis is a former ethical hacker (someone paid to break into systems legally to test them) who also helped defend critical national infrastructure. He saw that security scanners found plenty of problems but left teams drowning in alerts, so he built a tool that sorted what mattered from the noise. According to its own timeline, the company won its first paying customer in 2015, joined GCHQ's Cyber Accelerator in 2017, introduced its mascot Greg in 2019, and passed 3,000 customers in 2025. It is registered in England, and job adverts mention a dog-friendly office in Shoreditch, London, though many staff work remotely. In 2023 it was the only cyber company on the Deloitte UK Technology Fast 50, ranked 38th. We did not find headcount.
Its mission, in its own words, is "to make cybersecurity accessible for the 99%", meaning the many organisations that cannot afford a large security team. Its values are: enjoy the journey, focus on creating value, the best idea wins, achieve big things in small steps, and respect each other.
Products include Vulnerability Management, Attack Surface Management (tracking everything a company shows to the internet), Cloud Security, AI Pentesting (penetration testing means ethically attacking a system to find faults) and GregAI, an AI security analyst. It also gives away free tools such as cvemon and Autoswagger. Named customers on its site include the NHS, Virgin Active, Fujifilm and The Alan Turing Institute, which are the company's own claims.
Intruder is a smallish company where the leadership team includes a chief technology officer, a head of people and a chief security technologist. A technical support specialist advert described the job as early career, said cyber security graduates were encouraged to apply and advertised £35,000 to £40,000 plus share options, 28 days' holiday, private healthcare, optional socials and a company offsite in Croatia. It was fully remote with the Shoreditch office available. That advert is undated, so treat it as an example. The Security Consultant listing we found asked for proven offensive security experience, so it is not a graduate role. We found no graduate or intern scheme, so check Intruder's careers page.
Website: www.intruder.io
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