LLM Applications Engineer: Design Reliable AI Workflows

ActAI; Warszawa; On-site; PLN 180,000 - 240,000; Full time

Job summary

ActAI in Warszawa is seeking an LLM Application Engineer to build the intelligence layer that powers ActAI's AI experiences. You will work at the intersection of LLMs, software engineering, and product—designing agent workflows, improving model behaviour, and turning AI capabilities into reliable user experiences.

You will own problems end-to-end, from understanding user needs to integrating models and tools, building evaluation systems, and continuously improving AI behavior in production.

Qualifications

• Strong software engineering fundamentals.
• Hands-on experience with LLMs, generative AI, or agent-based systems.
• Experience designing prompts, workflows, evaluations, or AI behaviour.
• Ability to write clean, production-quality code.
• Comfortable working across abstraction layers (model - system - product).
• Strong problem-solving skills in ambiguous, fast-moving environments.
• Bias toward shipping, iteration, and continuous improvement.

Responsibilities

• Build and ship LLM-powered applications and AI agent workflows.
• Design systems for reasoning, planning, memory, tool use and multi-step execution.
• Build reliable orchestration pipelines that turn probabilistic model outputs into predictable, observable, and safe actions.
• Integrate LLMs with APIs, databases, search, internal services, and external tools.
• Develop prompting, context engineering, structured outputs, tool-calling, and other techniques to improve model behaviour.
• Build evaluation frameworks and datasets to measure AI quality, reliability, and regressions.
• Debug AI systems across the entire stack—from model behaviour and prompts to orchestration, backend services, and product UX.
• Optimise AI systems for quality, latency, and cost.
• Work closely with product and engineering teams to turn ambiguous product problems into working AI solutions.
• Establish production practices for observability, tracing, experimentation, evaluation, and continuous improvement.

Skills

LLM experience

Software engineering

Prompt engineering

Production code

Cross-functional work

Tools

Agent frameworks

Vector databases

PyTorch/JAX

Job description

ActAI in Warszawa is seeking an LLM Application Engineer to build the intelligence layer that powers ActAI's AI experiences. You will work at the intersection of LLMs, software engineering, and product—designing agent workflows, improving model behaviour, and turning AI capabilities into reliable user experiences.

You will own problems end-to-end, from understanding user needs to integrating models and tools, building evaluation systems, and continuously improving AI behavior in production.