Fullstack Software Engineer Lisboa

Overview

Fullstack Software Engineer at Siena AI.

Meet Siena: Siena is the first intelligence layer for customer experience. We're creating an operating system of AI agents that learn, remember, and act across every customer touchpoint—from support conversations to shopping experiences to voice and social media interactions.

Siena powers shopping agents, builds persistent customer memory, generates actionable business insights, and creates empathetic interactions that feel human. We’re transforming how businesses understand and connect with their customers, turning every interaction into intelligence that improves the next.

The Role

As a fullstack engineer at Siena, you’ll own projects
-
- end, developing and optimizing features within our AI-powered customer support automation platform. You’ll work closely with product to shape the roadmap while building reliable,
- performance systems that power millions of monthly customer interactions across global brands.

What You’ll Do

• Design, build, and maintain scalable features across the full stack (frontend, backend, and infra).
• Collaborate with Product to break down scope into iterative,
  - impact releases.
• Integrate
  - edge LLM capabilities into real enterprise workflows.
• Work on an AI-first product, integrating LLM capabilities into enterprise customer support workflows.
• Solve complex engineering challenges, from optimizing API performance to refining microservices architecture.
• Maintain and improve cloud infrastructure (AWS) with a Dev
  Ops mindset.
• Exercise high agency and ownership—taking initiative, making decisions, and driving ideas to production.

Who You Are

• 3+ years building in Node. js, React, Type
  Script, and Express.
• Strong experience with Postgre
  SQL, Redis, and cloud environments (AWS: Fargate, Lambda, EC2, SQS).
• Familiar with CI/CD (Code
  Pipeline, Git
  Hub Actions, or similar).
• Experience with microservices and scalable systems.
• Product-driven—you care about the impact of what you ship, not just the code.
• AI-first—you are comfortable orchestrating coding agents and using tools like Cursor, Claude Code.
• Naturally curious and proactive; you don’t wait for instructions, you create momentum.

Bonus points

• Next. js, Python, or
  - driven architectures.
• Infra-as-code (Terraform, CDK).
• Experience integrating with LLMs in production.
• Event-driven architecture experience.

Why Siena?

• Meaningful impact. Your work directly shapes our product and company.
• Globally distributed team at the edge of CX and AI.
• Competitive salary plus potential equity or stock grants.
• Learning budget to support growth.
• Opportunity to build something new where your contributions matter most.
• AI fluency as a core competency.
• Challenging problems and a culture of innovation.

Our Values

We value curiosity, customer obsession, ownership, direct feedback, high standards,
- speed execution, and strong relationships. When things get tough, we adapt and keep pushing forward.

Our Approach to AI

We treat AI as a natural extension of ourselves, building an ecosystem of agents for research, debugging, writing, analysis, and code. We share knowledge through demos, collaborative workflows, and learning from each other’s AI practices. Siena provides equal employment opportunities to all employees and applicants 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.

Company Details

• Seniority level: Mid-Senior level
• Employment type: Full-time
• Job function: Engineering and Information Technology
• Industries: Technology, Information and Internet