Castillians

QA Engineer

• Conducting extensive penetration tests across networks, applications, cloud environments, and infrastructure
• Scanning the client's external exposure websites and domains to identify security vulnerabilities and performing vulnerability assessments, and providing risk-based remediation recommendations
• Lead Threat-Led Penetration Testing (TLPT) / TIBER engagements
• Utilizing Threat Intelligence methodologies to simulate realistic attack scenarios
• Producing detailed technical reports outlining findings, risk levels, and mitigation strategies
• Collaborating with security teams, SOC analysts, and blue teams to improve defensive strategies
• Staying updated on the latest attack techniques, tools, and industry best practices
• Developing and deploying custom tooling and malware for Red Team engagements
• Guiding and mentoring junior team members

Senior Penetration Tester

Backend Engineer

• Participate in software and architectural development activities
• Continue implementation of the Real-Time Reporting feature
• Conduct tests to identify issues and ensure stability
• Create a bug bash sheet for issue tracking

Senior Java Engineer

• Build, deploy, and manage the real-time communication backend to support live audio interactions
• Orchestrate end-to-end sessions between end users and backend AI services
• Integrate Azure Speech services (STT/TTS) and Azure OpenAI (LLMs) into real-time pipelines
• Develop and maintain REST and WebSocket APIs consumed by mobile and web frontends
• Handle session state, participant matching, reconnections, and failure recovery as the “traffic controller” for calls
• Ensure low-latency, highly available, and scalable infrastructure using containerized microservices
• Build backend logic to manage call lifecycle (start/end sessions)
• Match participants and track call state
• Implement reconnection and failure-handling mechanisms
• Act as the system’s “traffic controller” for real-time media sessions
• Support for microservices architecture and API scaling

Senior Backend Engineer

• Ensure end-to-end system functionality across mobile applications, web portals, and backend APIs
• Validate real-time communication features including call quality, stability, and performance
• Design and execute test scenarios for network instability, packet loss, and reconnection flows
• Perform functional testing across authentication, role-based access, dashboards, and API layers
• Identify, document, and track edge cases affecting user experience and system reliability
• Collaborate with engineering teams to reproduce, isolate, and resolve defects
• Contribute to continuous improvement of QA processes and test coverage
• Support regression testing for releases and hotfix deployments.

Senior Penetration Tester

Senior Java Engineer

Senior Backend Engineer

Senior QA Engineering