Seed Cybersecurity companies in London

Companies defending or attacking software, networks, and cloud infrastructure. Filtered to Seed-stage companies headquartered in London.

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Built from a search like: “Top Seed Cybersecurity companies in London”

Ranked by current headcount across Seed Cybersecurity companies in London. Refreshed monthly.

1
Intruder· London, England, United Kingdom
Intruder's continuous exposure management platform helps security, IT, and engineering teams stop breaches before they start. By unifying AI penetration testing, attack surface monitoring, cloud security, and vulnerability management in one intuitive platform, Intruder gives stretched teams an always-on security source of truth. Our approach focuses on continuous automated scanning using expertise and agentic solutions to ensure that the findings we deliver are accurate, prioritized by real-world risk, and ready to act on.Founded in 2015 by Chris Wallis, a former ethical hacker turned corporate blue teamer, Intruder is now protecting over 3,000 companies worldwide. Intruder has been awarded multiple accolades, was selected for GCHQ’s Cyber Accelerator, included on Deloitte’s Tech Fast 50 2023 list as the fastest-growing cybersecurity company in the UK and was named in G2’s 2026 Best Software Awards.============================We're hiring! https://careers.intruder.io============================
- Seed
- 81 employees
- Founded 2015
2
SecureFlag· London, England, United Kingdom
SecureFlag helps organizations prevent vulnerabilities at scale by embedding security into every stage of software development, from architecture decisions to the moment code is written.From secure design to secure code, we transform how enterprises manage application risk.AI coding assistants have rapidly changed the risk equation. Developers are shipping faster than ever—and shipping more vulnerabilities with them, at a pace traditional AppSec tools can't match.As a Developer Security Enablement Platform, SecureFlag brings hands-on secure coding training and automated threat modeling into one place:-ThreatCanvas generates complete threat models in seconds, making risks visible at the design stage—before AI-generated (or human-written) code ever hits the repo.-SecureFlag Training upskills developers in live development environments, teaching them to recognize and fix the exact vulnerabilities AI tools are most likely to introduce.-Compliance reporting delivers continuous, audit-ready evidence across standards such as ISO, SOC 2, PCI, HIPAA, and ASVS.What enterprise teams see:➔ 21% fewer new security tickets➔ 27% faster vulnerability remediation➔ 24% less time spent on security rework➔ 2.4x ROI within 12 monthsTrusted by 300+ organizations in 30+ countries to turn secure-by-design from a principle into a measurable security control.Book a demo to see SecureFlag in action.
- Seed
- 71 employees
- Founded 2019
3
Goldilock Secure· London, England, United Kingdom
In today’s hyper-connected digital world, protecting any organization's assets against novel, sophisticated and aggressive cyber threats means reversing that hyper-connection when needed...powerfully, completely and outside the view of adversaries. Cutting them off while maintaining control of systems is essential.Goldilock FireBreakTM already protects water, energy, transportation and government infrastructure, providing a balance of security and business continuity, as well as being the world's AI Kill Switch. Our FireBreakTM️ Physical Connection Controller is a new breed of device that is controlled remotely, invisibly to the network, and allows you to disconnect either entire networks or selected segments at the physical level. We enforce total physical isolation-based segmentation. Any network, whether large enterprise, service provider, critical infrastructure or defense sector, needs to protect services, data, and business operations. Using FireBreakTM️ physical connection controller “uniquely achieves what no other solution can.” says Gregory Akers, Advanced Security Research, CISCO. Goldilock delivers advanced cyber defense solutions for network and infrastructure protection at the physical layer. FireBreakTM️ is a powerful physical connection controller that remotely, and invisibly, allows the disconnection of either whole networks or selected segments.
- Seed
- 45 employees
- Founded 2020
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4
SURF SECURITY· London, England, United Kingdom
The business landscape is fundamentally changing – the way and location of work has been transformed. Furthermore, with mass migration to the cloud, SaaS is vital. All this creates new risks - numerous points of access from multiple devices and multiple locations increase the attack surface. To address these attacks, your security solution should fundamentally change as well. That's where SURF enters.SURF provides users with freedom of work, letting them interact with applications, data, and each other securely. It addresses the critical business asset neglected by security experts for years: The browser.The browser is the access frontier for everything: users, data, corporate assets, applications, development activities - and cyber criminals, too.SURF Security has transformed the browser into your strongest security asset while providing complete end-user privacy – all with full compliance. Through this centralized platform, SURF insists on identity-first access to all SaaS and corporate assets to guarantee a secured and frictionless user experience. SURF enhances security, performance, and productivity for end-users and applications – faster than ever before.
- Seed
- 32 employees
- Founded 2021
5
eXate· London, England, United Kingdom
eXate is a distributed software platform for enforcing data privacy, data protection, and dynamic attribute-based access controls on data in motion and data at rest. With fine-grained access controls, and the ability to apply the Principles of Least Privilege, eXate can automatically enforce data policies and control the flow of sensitive data within a firm and across geographic borders.With more than 2/3rd of the world's population being covered under data protection regulation, the demand for data privacy by consumers is at an all-time high. 87% of consumers have indicated that they will not do business with a company who does not protect their personal data. As a result, 94% of companies now share privacy metrics with their Boards, and it is getting exponentially harder for organisations to stay on top of current data privacy demands.
- Seed
- 29 employees
- Founded 2015

6
Redflags.· London, England, United Kingdom
A UK company developing products that reinvent the delivery of end-user security education and awareness training.
- Seed
- 28 employees
- Founded 2016
7
BLOCKAPT· London, England, United Kingdom
Award-winning BlockAPT is redefining cybersecurity with an AI-powered, autonomous, self-defending platform built to protect modern digital ecosystems at speed and scale.Built on Cybersecurity Mesh Architecture, BlockAPT unifies security, risk, compliance, cloud, infrastructure, and operational tools into one intelligent command layer. Vendor-agnostic, modular and highly scaleable by design, the platform unifies security, risk, compliance, cloud, infrastructure, and operational tools into a single intelligent ecosystem. It eliminates silos, reduces complexity, and enables organisations to detect, respond to, orchestrate, and neutralise threats in real time.Our AI-powered automation reduces manual workloads, accelerates response times, simplifies compliance, and delivers real-time visibility across on-premise, cloud, multi-cloud, and hybrid environments. With one-hour deployment and a flexible Pay-as-you-Grow model, BlockAPT helps organisations of all sizes to strengthen cyber resilience without disruption, optimise existing technology investments, and achieve measurable ROI from day one.The platform is built around three core modules:UNIFY - integrates tools, systems, data, and workflows into one intelligent real-time view.CONTROL - orchestrates and automates security operations in real time through AI-powered playbooks.QUANTUM - provides quantum-secure communication and asset protection for data in motion and data at rest.BlockAPT also delivers unique automated cloud migration across cloud and multi-cloud environments in just a few clicks, accelerating secure digital transformation.BlockAPT sits at the intersection of AI, autonomous cyber defence, platform consolidation, cloud transformation, and quantum-secure resilience - creating a compelling opportunity for customers, partners, investors, and potential acquirers.For more information:www.blockapt.com | raj.meghani@blockapt.com
- Seed
- 21 employees
- Founded 2019
8
Falconfeeds.io· London, England, United Kingdom
Falcon Feeds.io: Your 24/7 Cyber Threat Intelligence Partner.Falcon Feeds.io is a cutting-edge, cloud-native SaaS platform that specializes in cyber threat intelligence. It vigilantly monitors and delivers the latest security incidents and insights on threat actors from around the globe, around the clock. Our expansive coverage includes the surface web, Tor networks, and Telegram channels.With Falcon Feeds.io, you can:Continuous Monitoring: Keep a watchful eye on threat actors, ransomware attacks, DDoS attacks, and other security incidents around the clock.Comprehensive Analysis: Stay informed about the most affected geographies, industries, organizations, and domains in real-time.Unrestricted Access: Gain unlimited access to our extensive threat feed database to empower your security measures.Customizable Alerts: Configure alerts tailored to new threats related to specific threat actors, incident categories, countries, industries, organizations, and domains.Seamless Integration: Utilize our robust API and Webhook integration for a smooth and streamlined security workflow.Real-Time Notifications: Get instant notifications through Slack, Microsoft Teams, and email, ensuring you never miss a critical update.Falcon Feeds.io is not just a platform; it's a partner in your cyber defense strategy, designed to give you a decisive advantage against evolving digital threats.
- Seed
- 19 employees
- Founded 2023
9
MIRACL | The login you love· London, England, United Kingdom
MIRACL provides the world’s only user-friendly, single step Multi-Factor Authentication (MFA) and Digital Signing service. Secure MFA in 2 seconds.MIRACL Trust® ID blocks 98% of all attacks* and eliminates the need for outdated security practices such as passwords, SMS Texts, push notifications and key-cards. The use of true two-factor authentication coupled with the latest Zero Knowledge Proof (ZKP) technology means no personal data is stored or transmitted and there are no "honey-pots" of data exposed to attack keeping MIRACL Trust out of scope for GDPR.MIRACL Trust® Proof allows every user to cryptographically sign any digital asset such as a transaction payment, KYC document transfer, user uploaded content, user action or binding agreement.Usability is paramount, no additional user enrolment steps are required and users authenticate & sign using a simple PIN. Without the requirement for hardware, mobiles or fiddly second steps, your users will love the simplicity and you will appreciate the reduction in support and maintenance overheads.MIRACL Trust® integrates easily into any web or mobile application through a cloud-based service, and has no dependence on client hardware of any kind. Provisioned as a PAYG service at a fraction of the cost of competing hardware solutions or SMS texts, MIRACL Trust® ID can be integrated with any OIDC compliant platform such as ForgeRock, WSO2, Okta and Auth0 just to name a few.Capable of scaling to millions of users overnight, a combination of usability, security and cost make it possible to deploy strong MFA to large B2C networks where it was previously impossible or impractical.Learn more at: www.miracl.com* Calculated from the 2019 Verizon Data Breach Investigations Report, based on Man-in-the-Middle, Phishing and Credential Stuffing (bot) attack frequencies recorded in 2018.
- Seed
- 17 employees
- Founded 2011
10
Soveren· London, England, United Kingdom
Soveren is a sensitive data observability company that raised $10M from the who-is-who in security and enterprise SaaS: the founders and CEOs of Datadog, Snyk, Palo Alto Networks, Slack, Tessian, MuleSoft, DeepMind, and a former CISO of Amazon. We are also backed by the amazing founders of Airbnb, Deel, N26, Algolia, as well as tier-one London-based VCs.Our founders previously built a unicorn: Instamart, the largest grocery delivery business in Eastern Europe with $2B in revenue. The challenges we faced with protecting customer data from security breaches and privacy violations eventually inspired us to start Soveren.Our mission is to help leading organizations protect millions of consumer data records without slowing down their business. We have built our solution in partnership with the most innovative security leaders in Europe and the US. We are an ambitious team working remotely across Europe with a strong performance culture and relentless focus on building a best-in-class security company.
- Seed
- 15 employees
- Founded 2020

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Find engineers at Seed Cybersecurity companies in London

Searching for “engineers at top Seed Cybersecurity companies in London” surfaces this slice of the market. The list above ranks Cybersecurity companies headquartered in London whose latest disclosed round is Seed, by current headcount, drawn from public LinkedIn and Crunchbase records. With 18 matching companies in Refolk’s index, this is a tight read on where the Cybersecurity talent in London is heating up.

Three filters at once narrows the field hard. The companies that survive all three - Seed, Cybersecurity, in London - are usually the most targeted recruiting pool a hiring manager can ask for. Senior engineers, founding designers, and product leads here are about to become Cybersecurity’s next operators and angel investors.

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Refolk pulled Cybersecurity companies headquartered in London whose latest disclosed funding round is Seed from public LinkedIn and Crunchbase records, ranked them by current employee count, and kept those with at least 3 employees. The list refreshes monthly.

Last refreshed: Fri, 18 Sep 2026 07:53:30 GMT

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