API Penetration Testing Providers
API penetration testing focuses on the security of application programming interfaces, which form the backbone of modern web and mobile applications. Testers systematically evaluate REST APIs, GraphQL endpoints, SOAP services, and WebSocket connections for vulnerabilities including broken authentication, excessive data exposure, injection attacks, improper rate limiting, mass assignment, and broken object-level authorisation (BOLA).
Testing follows the OWASP API Security Top 10 and examines how APIs handle authentication tokens, enforce authorisation between users, validate input data, and protect against abuse.
API pen testing is increasingly important as organisations adopt microservices architectures, expose APIs to partners and third parties, and build API-first products. Insecure APIs are a leading cause of data breaches, making thorough security testing essential. API pen testing helps organisations that must comply with PCI DSS, HIPAA, SOC 2, and GDPR by identifying vulnerabilities that could lead to unauthorised data access or manipulation through API endpoints.
SECFORCE
Leading UK offensive security consultancy based in Canary Wharf, delivering CREST-accredited penetration testing and adversary simulation to organisations with the most demanding security requirements.
NCC Group
Global cybersecurity consultancy with CREST, CHECK, and CBEST accreditation, renowned for deep technical research and comprehensive penetration testing services.
Nettitude
CREST, CHECK, and CBEST accredited UK consultancy within Lloyd's Register, delivering premium penetration testing for government and critical infrastructure.
NetSPI
Leading penetration testing firm with the Resolve platform for continuous attack surface management, trusted by nine of the top ten US banks.
Trustwave
Global managed security provider with the elite SpiderLabs penetration testing team and deep PCI DSS compliance expertise.
Bridewell
Fast-growing CREST and CHECK-accredited UK cybersecurity consultancy with deep expertise in critical national infrastructure sectors.
Pentest People
CREST and CHECK-accredited UK penetration testing firm with an innovative SecurePortal platform and transparent pricing for mid-market organizations.
Mandiant
World-renowned cybersecurity firm now part of Google Cloud, delivering threat intelligence-led penetration testing and red teaming informed by front-line incident response experience.
Bishop Fox
Premier US-based offensive security firm known for elite penetration testers, cutting-edge research, and the Cosmos continuous attack surface management platform.
Rapid7
Creators of Metasploit offering enterprise penetration testing integrated with their comprehensive vulnerability management and security operations platform.
Coalfire
Compliance-focused cybersecurity advisory firm and FedRAMP 3PAO specializing in penetration testing that meets stringent regulatory requirements.
WithSecure
Leading European cybersecurity firm offering penetration testing with deep expertise in EU regulatory compliance including GDPR, NIS 2, and TIBER-EU.
Claranet
CREST and CHECK-accredited European managed services provider delivering penetration testing with deep infrastructure and cloud hosting expertise.
HackerOne
World's largest ethical hacker platform with over one million researchers, offering bug bounties and structured penetration testing to the US DoD and Fortune 500.
Integrity360
CREST-accredited pan-European cybersecurity services provider delivering penetration testing and managed security from Dublin with a strong UK and Ireland presence.
Black Hills Information Security
Community-driven penetration testing firm known for free security education, open-source tools, Wild West Hackin' Fest, and practical offensive security services.
SEC Consult
Leading European cybersecurity consultancy from Vienna with a prolific vulnerability research program and deep expertise in IoT and embedded systems security.
IOActive
Elite boutique security consultancy specializing in IoT, SCADA/ICS, embedded systems, and hardware security research with world-renowned researchers.
Secureworks
Dell Technologies-backed cybersecurity firm with elite Counter Threat Unit intelligence informing enterprise penetration testing and adversary simulation.
Trail of Bits
Elite security research firm specializing in source code review, blockchain auditing, and building industry-standard open-source security tools.
Rhino Security Labs
Cloud security penetration testing specialists known for the Pacu AWS exploitation framework and deep expertise across AWS, Azure, and GCP environments.
Praetorian
Offensive security firm founded by former DoD professionals, offering elite penetration testing and the Chariot continuous attack surface management platform.
Offensive Security
Creators of OSCP, Kali Linux, and Exploit-DB, offering elite penetration testing services from the team that trains the world's ethical hackers.
Bugcrowd
Leading crowdsourced security platform offering managed bug bounty programs and crowd-powered penetration testing with hundreds of thousands of ethical hackers.
Synack
FedRAMP-authorized crowdsourced penetration testing platform combining vetted elite hackers with AI-powered Hydra technology for continuous security testing.
Aon Cyber Solutions
Cybersecurity consulting division of global insurance leader Aon, uniquely combining penetration testing with cyber risk quantification and insurance expertise.
Securin
Vulnerability intelligence-driven penetration testing firm providing contextual security assessments informed by threat actor exploitation data and ransomware tracking.
BreachLock
Cloud-based Penetration Testing as a Service platform combining AI-driven automation with expert manual testing at accessible price points.
Cure53
Berlin-based specialists in web security, browser security, and cryptographic auditing, trusted by the world's leading VPN providers and privacy tools.
Cobalt
Pioneer of Pentest as a Service, delivering fast, platform-based penetration testing with a vetted global community of security researchers.
API Penetration Testing FAQs
What types of APIs can be tested?+
REST, GraphQL, SOAP, gRPC, WebSocket, and any custom API protocols can be tested. Testers need API documentation or access to the application that consumes the API.
Do you need API documentation for testing?+
API documentation (Swagger/OpenAPI specs, Postman collections) helps testers work more efficiently but is not strictly required. Testers can discover and map API endpoints through application analysis.
How is API pen testing different from web app pen testing?+
API pen testing focuses specifically on the API layer - authentication, authorisation, data validation, and business logic at the API level. Web app testing covers the full application including the user interface.