Penetration testing is used to test the cybersecurity of businesses by simulating real-world cyberattacks. Its function is crucial, as pen testing identifies flaws and vulnerabilities in vital systems that can otherwise go unnoticed. With so many penetration testing providers available, it can be difficult to find a match for your business.
We’ve compiled a carefully tailored list of the best penetration testing companies in the UK based on our experience. Below, we’ve broken down their service offering and highlighted how you can prioritise your business needs by choosing the right provider.
List of penetration testing companies
- OnSecurity
- Qualysec
- Bulletproof
- Redscan
- NCC Group
Top 5 penetration testing companies in the UK
Here’s a list of the top 5 penetration testing companies in the UK:
1. OnSecurity
OnSecurity combines expert-led security assessments with an AI-powered approach to revolutionise traditional penetration testing. With a fully digital, on-demand platform, businesses that partner with OnSecurity benefit from rapid scheduling and reporting, with real-time progress tracking that makes accessing actionable insights easier than ever.
- Continuous protection: Ongoing vulnerability scanning and real-time threat intelligence keep your infrastructure safe between pentests, helping teams identify critical security issues 40% faster.
- AI-powered automation: Combined with expert input, pentests deliver faster, accurate results, with up to a 95% reduction in vulnerability management.
- Customisable and flexible solutions: Tailored features that exclude noisy subdomains, reducing complex systems into one, easy-to-navigate platform so businesses can focus on what matters.
- Clear pricing structure: Combine pentest and vulnerability scanning payments into one centrally-managed monthly payment. Get an instant bespoke quote based on just a few questions.
- Expert-led, proven security: With 40 years of ethical hacking experience from the founders, the team can spot weaknesses and keep you ahead of evolving threats.
- CREST-accredited UK-based pentesters from OnSecurity help businesses of all sizes to gain immediate insights that strengthen security information and prevent cyber exploitation.
- Trusted by global brands: From enterprises including Lidl and Retail inMotion, to giffgaff and gousto. There are plenty of case studies and positive reviews to support the credibility of this pentest service provider. OnSecurity is also proud to be one of the highest-rated pentest vendors in the world based on G2 reviews.
Pentesting service types include:
- Web application testing: Pen testing for web apps, servers and websites
- Mobile application testing: iOS, Android and business application testing
- Cloud security: Testing across AWS, Azure and GCP cloud environments
- Social engineering: Targeted phishing simulations to strengthen awareness
- Physical penetration: On-site assessments to safeguard physical assets
- Phishing simulation: Phishing testing of email vulnerabilities
- Internal infrastructure: Internal network and insider threats
- External infrastructure: Perimeter defence testing to fortify external security
The platform also features add-on vulnerability scanning and threat intelligence for continuous scanning to detect network vulnerabilities and attack surface monitoring.
2. Qualysec
Qualysec offers pentesting services designed to help clients identify and mitigate cybersecurity risks effectively. Specialising in network security, web application security, and cloud security, they provide comprehensive assessments to uncover hidden vulnerabilities. Their expert team adopts a predominantly manual testing approach, ensuring depth and accuracy in every engagement.
3. Bulletproof
Bulletproof provides penetration testing services to businesses across the UK. Focusing on network, web app, mobile and cloud pentesting, they have a track record of protecting businesses with automated scans and remediation advice. Alongside pentesting, they also provide data protection, information security and cybersecurity training.
4. Redscan
Part of the Kroll business network, Redscan provides offensive security assessments and consultancy, including penetration testing and breach and attack simulations. Utilising ethical hacking engagements, they help businesses to protect and defend against evolving cybersecurity threats.
5. NCC Group
NCC Group is a global cybersecurity firm offering penetration testing, incident response management and recovery solutions. As pentesting providers, they focus on both proactive and reactive security, providing security consulting to help organisations build resilient cyber strategies. Known for their technical expertise, their services help clients identify vulnerabilities, respond to threats, and enhance overall cybersecurity.
What should you look for when choosing the best penetration testing provider for your business?
When choosing the best penetration testing provider for your business, there are a number of things you’ll need to consider to ensure that your provider has the experience and expertise you need:
- Many providers offer a broad range of cybersecurity services, so you’ll want to prioritise those that deliver quick, efficient results, giving your business the insights to address and patch gaps in your security.
- Consider providers with experience completing effective pentests in your industry or sector.
- Look for a provider that specialises in penetration testing and uses innovative techniques, such as combining AI-powered tools and expert-led manual testing.
Best penetration providers in the UK services checklist
Narrowing down the top penetration testing providers may seem like a daunting task, but it’s all about choosing a service that can best respond to the unique needs of your business. When selecting the best penetration testing company, be sure to:
Choose the right type of pentest for your business needs
Start by identifying the critical systems and resources your business relies on, like customer databases, internal networks, or cloud infrastructure. This will help you to refine which areas would benefit most from targeted testing. A clear understanding of these priorities can help you select a penetration testing provider in the UK with the right expertise to protect your most valuable assets effectively and efficiently.
Check certifications/accreditations
It’s essential to select an accredited penetration testing provider that aligns with the latest industry standards and compliance requirements. For example, CREST accreditation demonstrates a commitment to enforceable codes of conduct, with quality assurance applied to both team members and internal processes.
This is especially important for businesses in sectors handling sensitive or regulated data, such as finance, healthcare, or government. Accredited providers offer assurance that their testing methods are thorough, up-to-date, and capable of protecting critical systems and infrastructure.
Understand reporting timelines
Even some of the best pentesting services can take days or even weeks to deliver reports, delaying your ability to act on critical vulnerabilities. Slow reporting can leave your business exposed, so it’s important to prioritise penetration testing providers that offer quick turnaround times without compromising on the depth and quality of their analysis. Fast, actionable reporting enables your team to respond swiftly and effectively to potential security risks, whilst seamless integrations with existing systems don’t disrupt day-to-day workflow.
How does OnSecurity’s top penetration testing service support your business?
OnSecurity’s top-tier penetration testing services can support your business by delivering quick, effective assessments across a wide range of cybersecurity threats. Our expert-led team tests for vulnerabilities across web applications and cloud security, external infrastructure, phishing and social engineering and more, ensuring your defences are robust from all angles. We monitor for insider threats and simulate real-world attacks to expose weaknesses before attackers do. We deliver our results 30 days faster than the industry standard, with real-time report findings available in as little as 8 minutes.
Want to find out more about how OnSecurity can help you to proactively respond to cyber threats? Get an instant quote on our pentesting services.
