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AI Engineer
REMOTE · WORLDWIDE
$50K–$68K
Contract
SENIOR
About the Role
Ruby Labs is seeking a senior AI Engineer to shape AI infrastructure and drive production-ready LLM experiences. You will own advanced prompt systems, structured outputs, and complex LLM workflows using LangChain or LlamaIndex. The role involves observability, debugging, and evaluation using Langfuse and OpenRouter, with full ownership from experimentation to live production.
Responsibilities
- Advanced Prompt Engineering: designing complex prompt templates with conditional logic
- Structured Outputs & Schemas: implementing JSON mode, function calling, Zod/JSON schemas
- Prompt Engineering & Evaluations: building evaluation pipelines using Langfuse
- Tracing & Debugging: debugging LLM chains using Langfuse traces
- AI A/B Testing: running experiments across models via OpenRouter
- Data-Driven Decisions: using quantitative benchmarks for model deployment
- Output Scoring & Analysis: developing scoring systems for hallucination detection
- Model Performance & Fine-Tuning: re-evaluating models and fine-tuning when necessary
Requirements
- Deep knowledge of Node.js and Next.js
- Proven experience in dynamic prompt building
- Experience with OpenRouter for unified API management
- Understanding of LLM observability with Langfuse or similar
RL
Ruby Labs
San Francisco · US · 139+ employees
Ruby Labs is a technology company that creates and develops innovative consumer products across the health, education, and entertainment sectors. Founded in 2018, the company operates with a self-funded, engineering-led, and agile methodology to build platforms that serve millions of users globally.
