Build AI systems that actually work in production. Own intelligence, not just features. Shape how decisions are made.

We’re looking for a Senior LLM / AI Engineer for one of our clients — an early-stage AI startup. This is a hands-on role for someone who doesn’t just experiment with AI, but has built, deployed, and optimized real AI agents in production.

This role is for someone who takes full ownership of AI systems — from architecture to performance. You’ll work at the intersection of LLMs, backend systems, and product, building intelligent agents in a fast-moving, high-impact environment where security and reliability matter.

Your responsibilities will include:

• Build and optimize AI agents used in real business workflows;
• Design and implement end-to-end RAG pipelines (retrieval, ranking, prompting);
• Work with vector databases and knowledge graphs to structure and retrieve data;
• Integrate LLMs (Anthropic Claude, Mistral) into scalable backend systems;
• Analyze logs, traces, and model outputs to improve agent performance;
• Own observability and debugging of AI systems (LangSmith or similar tools);
• Design backend architecture for AI-powered features (APIs, services, security);
• Collaborate closely with technical leadership to shape solutions;
• Contribute to cross-functional tasks across AI, backend, and occasionally frontend;
• Ensure high standards of data security, privacy, and system reliability.

What we expect from you:

• Strong experience as a Senior AI / LLM Engineer or strong Senior Full-stack Engineer with deep AI focus;
• Proven production experience building and deploying AI agents;
• Hands-on experience with Anthropic (Claude) and cloud-based AI workflows;
• Strong experience with RAG pipelines and retrieval systems;
• Experience working with vector databases and/or knowledge graphs;
• Experience with observability tools (LangSmith or similar) and logs analysis;
• Strong backend engineering mindset (APIs, system design, security);
• Ability to work independently and take ownership without micromanagement;
• Experience working in startup environments or low-structure teams;
• Strong problem-solving skills in ambiguous environments;
• English level: B2+ (C1 preferred);
• Availability to work in EU time zone.
• Nice to have:
• Experience with AWS (Lambda, infrastructure);
• Basic understanding of frontend (React);
• Experience with Supabase or similar databases;
• Experience working in early-stage startups (0 → 1 phase).

We offer:

• Opportunity to work in a Top-employee company (DOU 2025);
• Interesting projects and challenges that accelerate professional and personal growth;
• Work with a creative, proactive, and empathic team;
• Comfortable, stylish office in Kyiv with generator/battery backup;
• Minimal bureaucracy, regular feedback, and team support;
• Equal salary, medical insurance, paid courses;
• Team-building events: parties, online activities, picnics, and more.