Senior AI Engineer

Ruby Labs

. Take complete ownership and deliver major AI engineering features within agreed timelines.

Posted 6/9/2026full-timeRemote • 🇷🇸 SerbiaSeniorWebsite

Tech Stack

Tools & technologies

JavaScriptNext.jsNode.jsPostgresPythonRedisTypeScript

About the role

Key responsibilities & impact

Take complete ownership and deliver major AI engineering features within agreed timelines.
Own AI output quality, structure, and predictability across all user-facing AI interactions.
Design, implement, and maintain output-type-based AI systems, including segmentation, routing, and enforcement.
Ensure consistent output structure and formatting across different LLMs for the same request type.
Integrate and orchestrate multiple LLM providers via OpenRouter, managing model selection, fallback strategies, and cost optimisations.
Design and orchestrate tool-using and agentic AI workflows, defining clean tool contracts (including MCP-based tools), function-calling interfaces, and reliable AI-to-system integrations.
Build and maintain complex, multi-step LLM workflows, including with orchestration frameworks such as LangChain or LlamaIndex, for advanced reasoning, context reuse, and retrieval.
Design and manage production prompt systems with dynamic prompting, context injection, and conditional logic.
Own the deployment and release of LLM experiments, prompt management, and Langfuse-based evaluation pipelines.
Run A/B tests across models, analyse results, and present data-driven impact assessments of AI features and experiments.
Monitor AI system metrics, quality signals, latency, and release health using Langfuse and other observability tools.
Deep-debug complex LLM chains using Langfuse traces, identifying bottlenecks and optimising for cost, latency, and context-window usage, and build output-scoring systems to root-cause hallucinations and logic errors.
Write clean, scalable, and maintainable TypeScript code across the Next.js and Node.js stack.
Build reliable backend logic for AI systems, with strong error handling, request validation, fallback flows, and predictable behaviour in production, including reliable tool execution and AI-to-service integrations.
Ensure high code quality through testing, code reviews, and clear engineering standards.
Monitor, troubleshoot, and improve production performance, reliability, and system health.
Drive maintainability and technical quality through solid architecture, refactoring, and disciplined release practices.

Requirements

What you’ll need

6+ years of backend/full-stack software engineering experience, including production-grade TypeScript/Node.js. Experience with Next.js and/or Python is a plus.
2+ years of experience building AI/LLM systems in production. Less experience may be considered for exceptional candidates.
Deep hands-on experience working with LLM APIs (OpenAI, Anthropic, or similar) in production environments.
Experience with Agentic AI, multi-agent orchestration, tool-based workflows (function calling/tool execution), and/or RAG pipelines, including indexing, retrieval, and re-ranking.
Experience with LLM observability tools such as Langfuse, LangSmith, or similar platforms.
Experience with AI gateways and model routing solutions, such as OpenRouter or equivalent technologies.
Solid understanding of Redis and relational databases, such as PostgreSQL.
Exceptional ownership mindset and personal responsibility for engineering quality and delivery.

Benefits

Comp & perks

Remote Work Environment: Embrace the freedom to work from anywhere, anytime, promoting a healthy work-life balance.
Unlimited PTO: Enjoy unlimited paid time off to recharge and prioritize your well-being, without counting days.
Paid National Holidays: Celebrate and relax on national holidays with paid time off to unwind and recharge.
Company-provided MacBook: Experience seamless productivity with top-notch Apple MacBooks provided to all employees who need them.
Flexible Independent Contractor Agreement: Unlock the benefits of flexibility, autonomy, and entrepreneurial opportunities. Benefit from tax advantages, networking opportunities, reduced employment obligations, and the freedom to work from anywhere.

ATS Keywords

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Hard Skills & Tools

TypeScriptNode.jsNext.jsAI systemsLLM APIsmulti-agent orchestrationfunction callingtool executionRedisPostgreSQL

Soft Skills

ownership mindsetpersonal responsibilityengineering qualitydelivery