Software Engineer, AI (Level determined by experience)

AllegisCyber Capital; United Kingdom; On-site; GBP 90,000 - 130,000; Full time

Job summary

Synack, a security tech company, seeks a Senior Software Engineer (AI) in the UK to design and ship autonomous AI agents for penetration testing within sandboxed environments. You will own end-to-end systems, improve prompts, tool integration and cost optimization while collaborating with security researchers.

This remote UK role requires strong Python and Go, production systems experience, and familiarity with LLMs, RAG, and agent frameworks.

Qualifications

• 4+ years of software engineering experience.
• Experience building and scaling production systems.
• Strong Python background; willingness to learn Go.
• Hands-on AI apps using LLMs and agentic frameworks.
• Experience withDocker, Kubernetes and cloud platforms (GCP preferred).
• Experience with tool integration, prompts, evaluation and guardrails.
• Familiarity with microservices, gRPC and async messaging.

Responsibilities

• Build AI agents that automate penetration testing end-to-end.
• Stand up sandboxed lab infrastructure and orchestration.
• Ship features from ideation through production with guardrails.
• Improve agent performance: prompting, tool orchestration and cost.
• Lead code reviews and design sessions; mentor teammates.
• Collaborate with security researchers to translate hacking into agent behavior.

Skills

Software engineering

Production systems

Python

Go

LLMs and agent frameworks

Tool integration

Prompt design

Evaluation

Guardrails

Docker

Kubernetes

gRPC

Pub/Sub

Kafka

Cloud (GCP)

Security mindset

Communication

Tools

Docker

Kubernetes

gRPC

Pub/Sub

Kafka

LangGraph

Go

Job description

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. For more information, please visit www.synack.com.

We are looking for a Senior Software Engineer (AI), where you'll design and ship AI agents that plan, reason, drive security tooling and surface exploitable vulnerabilities, running autonomously inside sandboxed environments. It's a hands‑on senior role spanning applied AI and cybersecurity. You'll own systems end to end and raise the technical bar for the team around you.

Sounds interesting? Keep reading…

Please note: This is a remote position based in the UK. We can only hire citizens of the United Kingdom for this role. Given the nature of the work, the role may be subject to nationality, residency and security‑clearance checks.

Here’s what you'll do

• Build AI agents that automate penetration testing: planning, tool use, reasoning over findings, and acting safely within scope.
• Stand up and run the sandboxed cyber‑lab and range infrastructure, containerised on Kubernetes, where these agents execute offensive tooling.
• Ship features from ideation through production, including evals, guardrails and monitoring.
• Improve how our agents work: prompting, tool orchestration, evaluation, and cost.
• Lead code reviews and design sessions, and help the engineers around you grow.
• Work closely with our security researchers to translate how they hack into how our agents operate.

Here’s what you’ll need

• 4+ years of software engineering experience
• Proven ability to build and scale production systems
• Strong Python, polyglot codebase
• Fluent or willing to learn Go
• Hands-on experience building and operating production AI applications using LLMs and agentic frameworks (e.g., RAG, MCP, LangGraph or similar), including tool integration, prompt design, evaluation, guardrails, and token/cost optimization.
• Demonstrate ability to create reliable agents (prompting, evaluation, guardrails, understanding of token and cost optimization
• Capable leveraging Docker, Kubernetes, isolated sandbox, cloud experience GCP preferred
• Brings a disciplined testing approach to microservices gPRC, API design, async messaging (Pub/Sub, Kafka)
• Passionate desire to understand how systems get compromised
• Clear communication
• Collaborative ability to partner across teams

Nice To Have

• Offensive security experience: penetration testing, red teaming, CTF, or security tooling.
• Experience driving security tools programmatically or automating an attack chain.
• Startup experience, where scope is broad and priorities move fast.

Ready to join us?

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!

As a candidate, Synack cares about your privacy. Please view our candidate privacy policy.

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

Salary is determined by a combination of factors including location, level, relevant experience, and skills. The compensation package for this position may also include equity, and benefits. For more details about our benefits, please see our benefits overview. Then for the Employer code, enter: synack