Senior AI Engineer

Welcome! Super excited you dropped by 🥳
Let's redefine cyber security expertise standards and connect business - community through highly engaging hacking experiences. (Find out more insights about Hack The Box culture in our career site).

✨The core mission of the Senior AI Engineer:

Join our fast-growing team at the intersection of cybersecurity and AI, where you'll lead the end-to-end delivery of agent-powered applications that protect enterprises at scale. As a Senior AI Engineer, you'll own feature development across Python/Elixir APIs and modern agent-frameworks (LangChain, Argo, CrewAI, SmolAgents).

Our culture prizes autonomy, technical craft, and the drive to ship secure software that outsmarts attackers.

🏢 Location &  Work Mode:

Options: Preferably UK or Greece but open for Europe

Fully Remote / Hybrid (2 days in the office, 3 days remote, plus one month of work from anywhere) - If only in Greece:  When hiring in Greece, we’re open to candidates from all locations. Those based within 55 km of our Athens office will follow a hybrid work model. For candidates located beyond that radius, a fully remote arrangement is available.

🍺 The fellowship you’ll be joining:

Reporting to the VP of Artificial Intelligence, you will be part of a 7 people team. You'll collaborate with product, design, and security researchers to turn complex detection and response workflows into intuitive, intelligence-driven user experiences—while mentoring engineers and shaping our technical roadmap.

⚔️ Technology tools & weapons you’ll be using:

• Python, Elixir, Api design, AI frameworks & Agents, Semantic search / vector databases, Prompt engineering, GCP/AWS services

🚀 The adventures that await you after becoming Senior AI Engineer at Hack The Box:

• Design and build with modern agentic frameworks like LangChain, Argo, CrewAI, SmolAgents and Google ADK to orchestrate multi-step reasoning, RAG pipelines, and secure tool use
• Implement and maintain REST APIs in Python (FastAPI) or Elixir that integrate LLM inference, vector databases, and streaming security data
• Ensure security and compliance in the data layer by applying least-privilege access controls and working with PostgreSQL with Pgvector, Redis, and other stores
• Mentor engineers and contribute to technical leadership, including code reviews and design sessions
• Document decisions and communicate clearly in a remote-first environment, contributing to a culture of thoughtful async collaboration

🏆 Skills, knowledge, and experience points required to unlock the role of the Senior AI Engineer at Hack The Box:

• Hands-on building with LangChain / LangGraph, Argo, CrewAI, SmolAgents or equivalent libraries to orchestrate multi-step reasoning, tool use, and RAG pipelines
• Proficiency writing, secure REST or GRPC services in Python (FastAPI) or Elixir that integrate LLM inference,vector stores, and streaming data
• Experience with Erlang /Elixir is a plus
• Solid SQL and document-store experience (PostgreSQL, Pgvector, BigTable/Cassandra) with attention to least-privilege access and compliance
• AI/ML deployment: Practical knowledge of prompt engineering, evaluation, and model-ops on cloud GPUs or serverless inference platforms
• Experience guiding feature squads, conducting design reviews, and driving coding standards / CI-CD best practices in a senior or tech-lead role
• Excellent written & verbal communication, especially in remote/async environments, with a bias toward documenting architecture and decisions

What your Hack The Box adventure will have in store: 

• 🎯You'll have the exhilarating opportunity to contribute to a product that is highly appreciated by users and the cybersecurity community at large
• 🎯 You'll experience a highly supportive and caring environment, fostering growth, flexibility, and autonomy
• 🎯 You'll embark on an exciting journey of continuous learning and problem-solving, leveling up as our organization grows
• 🎯 Most importantly, you'll have a blast at HTB 🥳 because fun is an essential ingredient in our recipe for success! Just wait until you see our global meet-ups! 

💰 The gems you’ll be enjoying as a Senior AI Engineer:

• Private health care
• Paid paternity leave
• 25 annual leave days
• Free lunch & snacks at the office
• 120€ Ticket Restaurant by Edenred
• Dedicated budget for training and professional development, participation in conferences
• Full access to the Hack The Box lab offerings; so you can learn how to hack 😉
• State-of-the-art equipment (mac, iPhone, and mobile plan)
• Flexible WFH (Hybrid Model) - Fully Remot