Meet Siena
Siena is the The Agent of Record for CX, built for consumer brands like Spanx, FIGS, Brooklinen, and Grüns.

It runs as a connected multi-agent stack on top of a shared intelligence layer: agents that sell, support, listen, handle social and voice across the entire customer journey, turning every conversation into signal you can act on.

The team
We are a small, fully distributed, integral team. We have built leverage into how we work, which is what lets a team this size move at the speed we do.
We hire athletes. Everyone here owns real outcomes, defaults to writing over meetings, communicates with directness, and acts the moment they see something worth acting on. Low ego, high standards, fast clock.
If you want to own real problems rather than close tickets, keep reading.
About the Role
As a Senior Full Stack Engineer, you will own meaningful parts of the platform end to end. You will take ambiguous problems, work out the right approach, and ship reliable, high-performance systems that real brands depend on every day.




You will work closely with product to shape scope and roadmap, make real architectural decisions within your area, and do your best work without being managed task by task.

This role is for engineers who want ownership and can carry it.

What You'll Do
- Own features and systems across the full stack, frontend, backend, and infrastructure, from problem definition through production.
- Partner with product to break down ambiguous scope and ship in iterative, high-impact releases.
- Make real architectural and design decisions in your area, and explain the reasoning so the team can build on it.
- Take cutting-edge language models into enterprise customer workflows, where reliability and safety actually matter.
- Solve hard engineering problems: API performance, microservices, scaling across channels and brands.
- Maintain and improve our AWS infrastructure with a DevOps mindset.
- Raise the bar around you. Share what you know, review thoughtf

📌 Senior Fullstack Engineer (Argentina)
🏢 Siena AI
📍 Argentina