AI Engineer

Ruby Labs Ltd.

Job Overview

Location

European Union

Job Type

Full-time

Full Job Description

📋 Description

• Own end-to-end delivery of major AI engineering features in production, ensuring timely execution and high-quality outcomes.
• Maintain and improve the quality, structure, and predictability of all user-facing AI outputs across multiple LLM providers.
• Design and implement output-type-based AI systems including segmentation, routing, and enforcement mechanisms to ensure consistent formatting.
• Integrate and orchestrate multiple LLM providers via OpenRouter, managing model selection, fallback strategies, and cost optimization across APIs.
• Build and maintain agentic, tool-using AI workflows with clean tool contracts, including MCP-based tools, and reliable AI-to-service integrations.
• Develop complex, multi-step LLM workflows using 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 to adapt responses based on user input and system state.
• Own the deployment, release, and evaluation of LLM experiments using Langfuse-based pipelines for prompt management and performance tracking.
• Run A/B tests across LLM models, analyze results, and deliver data-driven impact assessments of AI feature changes and experiments.
• Monitor AI system metrics including quality signals, latency, release health, and hallucination rates using Langfuse and other observability tools.
• Deep-debug complex LLM chains using Langfuse traces to identify bottlenecks and optimize for cost, latency, and context-window efficiency.
• Build output-scoring systems to root-cause hallucinations, logic errors, and structural inconsistencies in AI responses.
• Write clean, scalable, and maintainable TypeScript code across Next.js and Node.js stacks for backend AI systems.
• Implement robust backend logic with strong error handling, request validation, fallback flows, and predictable behavior under production conditions.
• Ensure high code quality through testing, code reviews, and adherence to engineering standards across the AI engineering squad.
• Monitor, troubleshoot, and improve production performance, reliability, and system health of AI infrastructure.
• Drive technical quality through architecture design, refactoring, and disciplined release practices to ensure long-term maintainability.

🎯 Requirements

• 6+ years of backend/full-stack software engineering experience with production-grade TypeScript/Node.js
• 2+ years of hands-on experience building AI/LLM systems in production
• Deep experience working with LLM APIs (OpenAI, Anthropic, or similar) in production environments
• Experience with Agentic AI, tool-based workflows (function calling/tool execution), and/or RAG pipelines
• Experience with LLM observability tools such as Langfuse, LangSmith, or equivalent platforms
• Experience with AI gateways and model routing solutions such as OpenRouter

🏖️ Benefits

• Remote Work Environment: Work from anywhere with flexibility in schedule and location
• Unlimited PTO: Unlimited paid time off to support well-being and work-life balance
• Paid National Holidays: Paid time off for recognized national holidays
• Company-provided MacBook: Top-tier Apple MacBook provided for all employees who need one
• Flexible Independent Contractor Agreement: Autonomy with tax advantages, reduced employment obligations, and freedom to work globally

Skills & Technologies

Python

JavaScript

TypeScript

Ruby

Data Science

Remote

Ready to Apply?

Apply Externally

You will be redirected to an external site to apply.

AI Job Fit Analysis

Pro

See exactly how your profile matches this role — strengths, skill gaps, and what to do about them.

Ruby Labs Ltd.

Visit Website

About Ruby Labs Ltd.

Ruby Labs Ltd. is a London-based product studio that builds and scales consumer subscription mobile and web applications. The company focuses on health, wellness, and productivity verticals, developing apps such as Hint, Able, and the award-winning fitness platform FitCoach. Using data-driven growth and proprietary technology, Ruby Labs rapidly prototypes, launches, and iterates products to serve millions of global users. The team combines engineering, product design, and performance marketing expertise to create sustainable digital businesses. Founded in 2018, Ruby Labs operates a portfolio of self-funded apps, emphasizing user privacy, scientific validation, and long-term customer value.

View Company Profile

Get more remote jobs like this

Subscribe to the weekly newsletter for similar remote roles and curated hiring updates.

Weekly remote jobs and featured talent.

No spam. Only curated remote roles and product updates. You can unsubscribe anytime.