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Siena AI

Staff Software Engineer

Reposted 17 Days Ago
Remote
Hiring Remotely in United Kingdom
Senior level
Remote
Hiring Remotely in United Kingdom
Senior level
Lead architecture and technical direction across the full stack, solve ambiguous cross-cutting problems, deploy LLM-powered features into production, improve reliability and scale, mentor engineers, and make strategic build/buy and platform decisions that shape long-term product delivery.
The summary above was generated by AI
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, global 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

This is a Staff-level role for an engineer who operates beyond their own projects. You will decide how core parts of the platform get built, raise the bar for the whole engineering team, and own the hardest technical problems we have.

You will work across the full stack and the full lifecycle: setting architecture, making the cross-cutting calls, and making the engineers around you measurably better. You will partner directly with product and leadership to shape what we build and how we build it.

High autonomy, high trust, high consequence. It is built for someone who wants exactly that.


What You'll Do
  • Set technical direction and architecture for major areas of the platform, and bring the rest of engineering with you.

  • Own our hardest problems end to end: the ambiguous, cross-cutting, high-stakes work where the right path is not obvious yet.

  • Make the build/buy and architectural calls that shape the platform for years, and write down the reasoning so others can build on it.

  • Take cutting-edge language models into production inside enterprise customer workflows, where reliability and safety actually matter.

  • Multiply the team. Raise the engineering bar through design review, technical mentorship, and the standard you set by example.

  • Identify the technical initiatives we should be running, rather than waiting to be handed them.

  • Keep us honest on reliability, performance, and scale as we grow across channels and brands.

Who You Are
  • You have operated at Staff level, or you are clearly ready to. You are the person other engineers turn to when a decision is hard.

  • 7+ years of software engineering, with a track record of technical leadership across teams or systems. Years are a floor, not the signal.

  • Deep full-stack strength in our core stack: Node.js, React, TypeScript, Express.

  • Strong with AWS in production (Fargate, Lambda, EC2, SQS) and with PostgreSQL and Redis.

  • Fluent in microservices and distributed systems, and clear on when not to reach for them.

  • Comfortable owning CI/CD and infrastructure with a real DevOps mindset (CodePipeline, GitHub Actions, or similar).

  • Product-minded. You think in customer outcomes and business impact, not tickets closed.

  • You have shipped LLM-powered features to production. This is a must, not a bonus. You know what breaks when models meet real users at scale.

  • Direct, low-ego, high-ownership. You fix first and explain after, and you give and take honest feedback without flinching.

Bonus Points
  • Next.js.

  • Infrastructure as Code (CDK, Terraform).

  • Python.

  • Event-driven architecture.

  • Background in customer support or CX software.

Why Siena?
  • Real ownership. You will own problems, not tasks, with the autonomy to solve them your way and the trust to do it without a manager in your inbox.

  • Work that ships and matters. What you build reaches real consumer brands fast.

  • A category we are creating. The Agent of Record is new ground, with unsolved problems and cutting-edge models, not a crowded field to compete in.

  • A team that respects your judgment. Globally distributed, async-first, low bureaucracy. We hire adults and treat you like one.

  • Great salary plus equity or stock grants. Own a piece of what you build.

  • Learning budget. If you are growing, so are we.

  • AI-fluency by default. Few places will push your work with production AI further or faster.

Our values

The people who thrive here are curious, customer-obsessed, and take ownership without being asked. They fix problems first and explain later. They're direct about feedback—both giving and receiving it—because they care more about getting things right than being polite.

They maintain high standards while moving at startup speed, and they build real relationships with teammates because they know that's how great work gets done. When things get tough, they adapt and keep pushing forward.


Our approach to AI

The people who thrive here treat AI like a natural extension of themselves. They've built their own ecosystem of agents - some for research, others for debugging, writing, analysis, or writing code. They know which AI works best for what problem.

Everyone gets premium accounts (ChatGPT, Claude, Perplexity Pro, Cursor, Lovable) plus a quarterly budget for new tools. But the magic happens in how we share knowledge. Demo days where someone shows off a clever workflows. Slack threads about which model handles a specific use case better. Learning from each other's AI workflows.

At Siena, we’re not just looking for people who can do a job. We’re looking for people who want to break boundaries, create the future, and reshape industries. If that’s you, we look forward to your application.

We use AI-assisted screening tools as part of our hiring process. All decisions are made by humans. You can request a human-only review at [email protected].

Siena provides equal employment opportunities to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability, genetics, sexual orientation, gender identity, or gender expression. We are committed to a diverse and inclusive workforce and welcome people from all backgrounds, experiences, perspectives, and abilities.

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