Senior Infrastructure Security and Operations Engineer
Unlimit is a London-based global fintech providing cross-border payment processing, business accounts, banking-as-a-service, card issuing, and crypto/stablecoin payment infrastructure.
About Unlimit
Founded in 2009, Unlimit operates a global financial-services platform for businesses, combining payment processing, local and international payment methods, multicurrency business accounts, banking-as-a-service APIs, card issuing, payment rails, and digital-asset on/off-ramp capabilities. The company is headquartered in London and operates across multiple continents.
Skills
Candidate Availability
Required and preferred rules are kept separate and reflect the wording in the original posting.
About the Role
You will strengthen infrastructure security controls and operate security monitoring, detection, investigation, and incident-response capabilities. You will manage vulnerabilities, harden systems, secure AWS and Kubernetes environments, and improve endpoint protection. You will also build AI-powered security workflows, integrations, scripts, and tools for alert triage, threat hunting, vulnerability prioritisation, and response while maintaining appropriate validation, access controls, and human oversight.
Requirements
- 6+ years of hands-on engineering experience, including at least 4 years in cyber security, infrastructure security, or security operations
- Technical background in IT infrastructure, systems engineering, cloud engineering, or platform engineering
- Experience implementing infrastructure security controls in complex production environments
- Experience with security operations, SIEM, detection engineering, incident response, and threat hunting
- Understanding of cyber attack tactics, techniques, procedures, and MITRE ATT&CK
- Experience with EDR/XDR, vulnerability management, and security monitoring
- Knowledge of Linux, networking, operating-system security, and infrastructure hardening
- Experience securing AWS, Kubernetes, and containerised workloads
- Python development skills and experience building security automation, integrations, and internal tools
- Experience developing AI-powered and agentic solutions, including LLM integrations, tool orchestration, autonomous workflows, and AI-assisted automation
- Experience integrating security controls and automation into infrastructure and DevOps workflows
Responsibilities
- Improve infrastructure security controls across the global technology environment
- Operate and enhance security monitoring, alert triage, incident investigation, and response
- Develop SIEM correlation rules, detection use cases, log analysis, and monitoring integrations
- Conduct threat hunting and use threat intelligence to improve defences
- Lead incident investigation, containment, remediation, and post-incident improvements
- Manage vulnerability scanning, prioritisation, tracking, remediation, and validation
- Harden servers, endpoints, networks, and cloud environments
- Develop security controls for AWS, Kubernetes, and containerised environments
- Optimise endpoint protection and detection capabilities using EDR/XDR technologies
- Administer and integrate SIEM, EDR/XDR, vulnerability-management, and infrastructure-security platforms
- Coordinate infrastructure penetration testing, validate findings, and support remediation
- Support IT and information-security audits through evidence collection and control validation
- Build AI-powered workflows for alert triage, investigation, enrichment, and response
- Develop security automation, integrations, scripts, and internal tools using Python, APIs, and AI frameworks
- Apply validation, access controls, and human oversight to AI-powered security workflows
