Senior Software Engineer, AI in London

Synack’s Penetration Testing as a Service platform manages customers’ attack surfaces by discovering new assets, pentesting for critical vulnerabilities and gaining visibility into the root causes of security risks. We are committed to making the world more secure by harnessing a talented, vetted community of security researchers to deliver continuous penetration testing and vulnerability management, with actionable results. Synack's PTaaS platform has uncovered more than 71,000 exploitable vulnerabilities to date, protecting a growing list of Global 2000 customers and U.S. agencies in a FedRAMP Moderate Authorized environment.

We are looking for a Senior Software Engineer (AI), where you'll take a hands‑on lead in designing and building cutting‑edge, AI‑centric systems tailored for the offensive security sector. You will directly drive product innovation at the intersection of AI and cybersecurity. You will lead by example, mentoring junior engineers and promoting a culture of ownership, technical excellence, innovation and continuous improvement.

Here’s what you’ll do:

• Design, implement and deliver scalable AI‑centric software systems.
• Drive the development of agentic AI capabilities for identifying vulnerabilities, automating penetration testing processes, workflow optimization and enhancing threat intelligence.
• Own and drive the end‑to‑end development of product features from ideation to production deployment and monitoring.
• Actively contribute to and drive the design and implementation of AI‑enabled systems, promoting effective SDLC processes.
• Lead technical discussions, code reviews and design sessions, sharing your expertise to uplift the team’s capabilities.
• Provide mentorship and support to junior engineers, encouraging professional growth and development.
• Collaborate closely with cross‑functional teams to integrate AI capabilities into broader systems and applications.

Here’s what you’ll need:

• 7+ years of experience in distributed‑systems and backend software engineering.
• Experience with AI technologies, e.g. LLMs, RAG, MCP, etc.
• Excellent grasp of token usage optimization and LLM cost optimization techniques.
• Expert knowledge of golang (4+ years) and solid hands‑on experience with Python.
• Strong experience and understanding of microservices, REST API design, gRPC, writing unit testing, BDD testing.
• Strong design skills required – UML is a bonus; exposure to Domain Driven Design desirable.
• Experience with asynchronous messaging technologies such as Google PubSub, Kafka.
• In depth knowledge of NoSQL and RDBMS technologies.
• Strong experience with Docker, Kubernetes, Cloud Environments (GCP preferred).
• Experience working on agile teams.
• Excellent communication and collaboration skills in all mediums.
• Experience working on and scaling a microservice‑based application.
• A proven ability to thrive in a collaborative environment involving different stakeholders and subject matter experts.

Nice To Have:

• Experience in a fast‑paced startup environment.
• Experience in Cyber Security.

Synack is committed to embracing diversity. Our people are our strength. Each addition to our team is an opportunity to grow and diversify our ideas, experiences, and viewpoints. We strive to be inclusive of Race, Ethnicity, Religion, Sex, LGBTQ+, Veterans, Disabilities, and Age. Synack welcomes you!

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This position has responsibility to ensure Synack’s security and privacy posture is maintained.

£150,000 - £180,000 Salary is determined by a combination of factors including location, level, relevant experience, and skills. The range displayed on each job posting reflects the minimum and maximum target for new hire salaries for the position across all UK locations. The compensation package for this position may also include equity, and benefits.