Senior AI Engineer — D2C Subscriptions (Remote)

Ruby Labs Ltd; United States; Remote; USD 150,000 - 240,000; Full time

Benefits offered by this job

Remote work

Unlimited PTO

Paid holidays

MacBook provided

Contractor agreement

Tax advantages

Job summary

Ruby Labs Ltd is seeking a Senior AI Engineer to own and scale the AI layer of one of our core D2C subscription products. You will design, implement, and optimize AI workflows spanning prompts, LLM tooling, and production deployment.

You will build robust automation, manage costs and latency, and collaborate with product teams to translate metrics into business impact. This role supports globally distributed teams with remote work.

Qualifications

• 5+ years of software engineering with Node.js, TypeScript, Next.js, and Postgres.
• Production browser automation experience with Playwright at scale.
• Experience with dynamic prompting and JSON mode in production.

Responsibilities

• Design dynamic prompt templates with conditional logic and context injection that maximise generation quality
• Enforce predictable outputs with JSON mode, function calling, Zod/JSON schemas, validators, and repair loops
• Own complex LLM workflows (LangChain, LlamaIndex, or custom) that integrate cleanly into application logic
• Build and maintain browser automation on Browserbase Functions and Playwright that traverses web flows reliably
• Classify screens with a model inside each traversal, and decide what the model handles versus deterministic code
• Ship automations as frozen, published workers — versioned, reproducible, and safe to roll back
• Orchestrate runs through Hatchet with retries, timeouts, and failure traces that explain every broken run
• Build evaluation pipelines — test datasets, LLM-as-a-judge, RAGAS-style metrics — and score responses and screen classifications in Langfuse
• Trace complex LLM chains to find bottlenecks in cost, latency, and context-window usage
• Run A/B experiments across models and prompts through an AI gateway (OpenRouter, Cloudflare AI Gateway); release only on quantitative benchmarks
• Re-evaluate models as new architectures emerge; fine-tune when domain requirements demand it
• Take AI features from experiment to live production on Cloudflare Workers and Containers, and stay accountable after release
• Manage rate limits, fallbacks, and model cost so features stay reliable at scale
• Resolve production incidents in owned AI and automation systems with documented root-cause analysis

Skills

Node.js

TypeScript

Next.js

Postgres

Tools

Playwright

Browserbase

LangChain

LlamaIndex

Cloudflare Workers

Job description

Ruby Labs Ltd is seeking a Senior AI Engineer to own and scale the AI layer of one of our core D2C subscription products. You will design, implement, and optimize AI workflows spanning prompts, LLM tooling, and production deployment.

You will build robust automation, manage costs and latency, and collaborate with product teams to translate metrics into business impact. This role supports globally distributed teams with remote work.