Note: The job is a remote job and is open to candidates in USA. Ruby Labs is a leading tech company that creates and operates innovative consumer products. They are looking for a Senior AI Engineer to own and drive the quality, reliability, and evolution of their AI systems in production, focusing on end-to-end delivery and collaboration with various teams.
Responsibilities
- 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 / 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 to root-cause hallucinations and logic errors
- Write clean, scalable, and maintainable TypeScript code across the Next.js / Node.js stack
- Build reliable backend logic for AI systems, with strong error handling, request validation, fallback flows, and predictable behavior 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
Skills
- 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
- Experience with AI-centered development tools such as Cursor, Claude Code, Windsurf, or similar platforms
- Familiarity with evaluation frameworks, including LLM-as-a-judge, RAGAS, or similar approaches
- Experience working in high-pressure startup environments with rapid product iteration cycles
- Experience with MCP (Model Context Protocol), including building MCP servers/clients or designing tool contracts for AI agents
- Experience with edge and serverless runtimes, such as Cloudflare Workers, and supporting services including KV, Durable Objects, Queues, R2, and D1
- Experience with payments, billing and checkout flows, or orchestration platforms
- Practical experience fine-tuning models for domain-specific tasks or achieving strict JSON/schema compliance
- Working proficiency in Python for data science, evaluation scripts, or AI tooling
Benefits
- 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. Read more about it here:
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