About Us 5Blue Software is an Israeli-Ukrainian software development company specializing in custom software development, staff augmentation, dedicated engineering teams, AI solutions, and CTO-as-a-Service. We help startups and mid-sized companies scale faster with vetted engineering talent across Europe.

About the Role

We are looking for a Senior AI Engineer to join one of our client projects — an early-stage US-based wellness AI startup. You will work as a fractional contributor, starting with a structured technical handoff from the outgoing engineering team, then transitioning into ongoing launch support and system maintenance. You will need to take real technical ownership, communicate clearly with the client, and hit the ground running with minimal onboarding from our side. Requirements 7+ years of software engineering experience Expert-level proficiency in AI/ML engineering Excellent spoken and written English (C1) — direct client communication is required 5+ years working with LLMs — Claude, OpenAI, or equivalent — in production environments Hands-on experience building agentic and multi-turn conversational systems Strong prompt engineering skills — system prompts, structured outputs, context management, cost vs. quality tradeoffs Experience with tool/function calling, memory layers, and RAG pipelines Familiarity with LLM observability — logging, tracing agent steps, monitoring output quality Understanding of prompt injection risks, output validation, and guardrails Ability to get up to speed on an unfamiliar codebase quickly and document it clearly Experience with messaging integrations will be a plus Self-directed and comfortable taking ownership with minimal oversight Does this position sound like a perfect match? We're eager to hear from you!