Software Engineer – Horizon

About the role

Sierra is building the Horizon platform, a next‑generation AI‑powered agent system that helps large brands deliver long‑horizon customer experiences. As a Software Engineer you will design and ship core infrastructure that enables agents to learn, improve, and operate across multiple channels over weeks or months.

Key responsibilities

• Build primitives for self‑improvement, including feedback loops, evaluation systems, memory, signals and decision‑making infrastructure.
• Design and ship long‑horizon agents that pursue complex business outcomes across voice, SMS, email and other channels.
• Identify reusable patterns and create platform abstractions, tools and APIs to accelerate future Horizon agents.
• Solve technically complex problems spanning orchestration, integrations, data, memory, signals, decisioning, observability and multi‑channel engagement.
• Translate validated prototypes into durable product capabilities and hand them off for continued deployment.

Required profile

• At least two years of professional software engineering experience building and scaling end‑to‑end production systems.
• Strong platform and systems engineering fundamentals with the ability to move between customer problems, product design and implementation.
• High agency, adaptability and clear communication, comfortable working directly with customers on complex business processes.

Required skills

• Python
• TypeScript
• Go
• React
• Workflow orchestration and event‑driven or distributed system design
• AI and large‑language‑model (LLM) integration
• Enterprise integrations, APIs and data pipelines

What we offer

• Unlimited paid time off and flexible work policies.
• Medical, dental and vision benefits for you and your family.
• Life insurance, disability, retirement plan and parental leave.
• Fertility and family‑building benefits, discretionary stipend and free alphorn lessons.