Senior Full-Stack Engineer (AI-Focused)

The Opportunity

An established SaaS product is rebuilding itself around AI, and this hire sits at the center of that shift, working side by side with the CTO. You'll put at least one AI feature in customers' hands within your first 90 days, and within a year your work should show up in adoption and retention numbers. Small team, real autonomy, and a product that already reaches millions of people.

What You'll Own

• AI features from interface to model call: UI, services, APIs, and the LLM layer underneath

• The in product AI agent, making it genuinely useful to customers, from prompt design through production evals

• LLM pipelines that hold up under real traffic: RAG, tool calling, agent orchestration, and evaluation

• MCP integrations that let customers work with the platform straight from their own AI tools

• Speed, reliability and cost of every AI feature, with metrics that tie latency and quality to customer value

• The AI first roadmap and architecture, shaped together with the CTO and product

• How the team builds with coding agents: workflows, guardrails, and review norms others adopt
  

What We're Looking For

• 6+ years as a full stack engineer on production SaaS

• Strong TypeScript or JavaScript on both frontend and backend, including a modern frontend framework

• Solid Elixir and Python

• LLM features shipped to production: model APIs, RAG, tool calling or agents

• A track record of measuring LLM output quality, through evals or similar systems

• Working knowledge of WebSocket traffic at high volume and how it shapes architecture

• Daily use of AI coding agents, with clear judgment on where human review and guardrails belong

• C1 or C2 English, comfortable going deep with engineers and presenting tradeoffs to leadership
  

Nice to Have

• Built an MCP server, connector, or other agent tooling

• Shipped an embedded JavaScript SDK or in app product experience

• Hands on with LLM tracing and observability tools

• Background in onboarding, product adoption, or PLG products
  

Tools and Stack

TypeScript / JavaScript · Elixir · Python · WebSockets · LLM APIs · RAG · MCP · Claude Code

Details

• Location: Remote, Argentina

• Time Zone: Strong overlap with US working hours required

• Salary: $84,000 - $100,000 usd yearly

• Type: Full time
  

About the Company

An established B2B SaaS platform that helps software companies onboard users and drive adoption through in app experiences. AI now sits at the core of its product strategy, and it reaches millions of end users across the US and Europe through its customers' applications.