Web application penetration testing is a systematic process of probing web-based applications for security vulnerabilities that could be exploited by attackers. Testers simulate real-world attacks against your web apps, targeting common weaknesses such as SQL injection, cross-site scripting (XSS), authentication bypass, insecure direct object references, and business logic flaws.
This testing follows methodologies like the OWASP Testing Guide and covers the entire application stack including front-end interfaces, APIs, session management, access controls, and server-side logic.
Web app pen testing is essential for organisations that handle sensitive data through online platforms, e-commerce sites, customer portals, or SaaS products. It helps identify vulnerabilities before malicious actors can exploit them, reducing the risk of data breaches, financial loss, and reputational damage. Regular web application penetration testing is also required by compliance frameworks including PCI DSS, SOC 2, and ISO 27001.
UK offensive security consultancy delivering CREST-accredited penetration testing, adversary simulation and CBEST, TIBER-EU and TBEST threat-led testing, mainly for financial services and other large organisations.
Penetration testing firm trusted by nine of the top ten US banks, with the Resolve platform for continuous attack surface management.
US penetration testing firm founded in 2011, running 600+ engagements a year with a fully remote, US-based team. Manual, expert-led testing across web, network, cloud, mobile, wireless, OT/ICS, and AI/LLM. Gartner Sample Vendor for PTaaS.
Munich- and Budapest-based embedded cybersecurity experts focused on financial services, automotive and mobility, manufacturing and industrial automation, energy and more. The services and platform go beyond compliance, supporting the requirements of the Cyber Resilience Act, PCI PTS, UN R155, ISO/SAE 21434 and other standards and regulations.
Global enterprise cybersecurity consultancy founded in 1999 in Oxford, holding rare CREST STAR-FS accreditation and delivering penetration testing, red and purple teaming, and PCI QSA services across five international offices.
Global Big Four professional services firm delivering CREST, CHECK, and CBEST-accredited penetration testing and red teaming services from London, serving the UK's largest enterprises and regulated organisations.
CREST and CHECK-accredited UK penetration testing and managed security provider formed in 2026 from Pentest People, Bulletproof, and Target Defense, with CREST STAR/TLPT-FS capability and the GuardNest vulnerability management platform.
Elite UK offensive security consultancy specialising in CBEST/STAR/TIBER red teaming, advanced adversary simulation, and CREST-accredited penetration testing for FTSE 100 clients.
Full-service London-based cybersecurity consultancy with CREST, CHECK, and NCSC accreditations delivering offensive testing, managed detection, and strategic advisory services.
Global managed security provider with the elite SpiderLabs penetration testing team and deep PCI DSS compliance expertise.
Manchester-based independent cybersecurity consultancy with over 20 years of experience delivering CREST and CHECK-accredited penetration testing, red teaming, and compliance certification services.
CREST and CHECK-accredited UK penetration testing consultancy with CBEST approval, specialising in infrastructure, application, and simulated attack assessments across the public and private sectors.
A typical web application penetration test takes 5-15 days depending on the complexity of the application, number of user roles, and depth of testing required. Large enterprise applications with multiple modules may require longer engagements.
Web applications should be pen tested at least annually, and ideally after every major release or significant code change. Compliance frameworks like PCI DSS require annual testing at minimum.
Automated scanners find common vulnerabilities quickly but miss business logic flaws and complex attack chains. Manual penetration testing combines automated tools with expert analysis to find deeper vulnerabilities that scanners cannot detect.