Principal AI Engineer

Location: Kyiv, Kyiv city, ua, Remote

Company Description

We are seeking a Senior/Principal AI Engineer to join our Stellar AdTech Business Unit at Sigma Software. This is a full-time role with a flexible hybrid/remote work option, ideal for an experienced professional passionate about designing production-grade agentic AI systems and influencing solution architecture for global AdTech clients.

You will work with cutting-edge multi-agent orchestration frameworks, contribute to presales activities, and design custom AI models that power large-scale, enterprise-ready solutions.
Why Join Us: Be part of a 300+ strong AdTech competence center, collaborate with top-tier global clients, and help shape the future of AI in advertising technology.

PROJECT

Our Stellar AdTech Business Unit specializes in Advertising Technology solutions and has been delivering innovative systems to global AdTech leaders and startups since 2008.
In this role, you will architect scalable AI-powered systems, translate complex business problems into actionable LLM-based solutions, and support presales by defining AI use cases, architectures, risks, and implementation roadmaps.

Job Description

• Consult clients during presales to assess AI readiness, constraints, and success criteria, translating visions into actionable requirements
• Prepare and present presales deliverables including architecture diagrams, assumptions, risks, estimates, scalability considerations, and implementation roadmaps
• Define AI use cases and agentic scenarios based on client needs
• Select and justify LLMs per use case based on requirements, cost, latency, safety, capability
• Architect multi-agent frameworks with orchestrator agents and MCP-style protocols
• Design and implement single-agent/multi-agent AI systems with defined roles, tool access, memory, safety boundaries
• Build orchestration logic (routing, delegation, retries, fallback strategies, consensus, human-in-the-loop flows)
• Develop RAG pipelines (data ingestion, chunking, embeddings, vector databases, hybrid retrieval, relevance optimization)
• Implement learning & feedback loops for continuous agent improvement
• Design custom or adapted models (prompt-tuned agents, LoRA fine-tuning, domain-inherited models)

Qualifications

• Designing and building AI-powered systems in production 
• Agentic frameworks, multi-agent collaboration, orchestrator/worker models 
• RAG pipelines, relevance tuning 
• Python and/or TypeScript, API design, microservices, cloud-native architectures 
• Presales consulting, translating business problems into AI solutions 

Additional requirements:

• Practical knowledge of multiple LLM providers (OpenAI, Anthropic, open-source)
• Ability to build/adapt models (prompt-tuned agents, LoRA fine-tuning, inheritance from foundation models)
• Knowledge of AWS Bedrock, Azure OpenAI, GCP Vertex AI
• Understanding governance, security, data residency, pricing models, enterprise integration for cloud AI platforms
• Production-grade mindset: observability, logging, security, PII handling, cost-efficiency
• Strong communication skills for explaining AI concepts to non-technical stakeholders
• English level: Upper-Intermediate
• Experience: 5+ years in AI engineering or related roles

WILL BE A PLUS

• Experience in AdTech domain
• Experience integrating AI into legacy or enterprise systems
• Familiarity with workflow automation tools
• Knowledge of DevOps practices, CI/CD, containerization