Software Engineer, Horizon

About Us

Sierra is the leading platform for customer-facing AI agents, working with many of the world's biggest brands — including The GAP, Rocket Mortgage, SoFi, Sutter Health, and SoftBank — to transform how they serve customers and grow their businesses. We are primarily an in-person company based in San Francisco, with growing offices across North America, Europe, and Asia.

What You’ll Do

• Build primitives for self improvement: Create the feedback loops, evaluation systems, memory, signals, and decisioning infrastructure that help long-running agents learn from outcomes and improve over time.
• Build the future of long-horizon agents: Design and ship agents that pursue complex business outcomes over days, weeks, or months across voice, SMS, email, and other channels.
• Turn 0-to-1 work into a platform: Identify patterns and build reusable systems, abstractions, and tools that make future Horizon agents faster and easier to launch.
• Solve technically complex problems: Build across orchestration, integrations, data, memory, signals, decisioning, observability, and multi-channel engagement.
• Shape the Horizon product: Surface platform gaps through hands-on implementation and work with product and engineering to define Horizon’s architecture and roadmap.
• Create a clean path beyond the POC: Once a solution is validated, translate what you built into durable product capabilities and enable a successful handoff for continued deployment.

What You’ll Bring

• Experience building and scaling end-to-end production systems.
• Strong platform and systems engineering fundamentals.
• The ability to move between customer problems, product design, and technical implementation.
• Strong technical judgment in ambiguous, fast-changing environments.
• A builder’s mindset and the ability to take products from zero to one.
• Comfort working directly with customers and understanding complex business processes.
• High agency, adaptability, and clear communication.
• At least two years of professional software engineering experience.
• Experience with Python, TypeScript, or Go and React.

Even Better

• Experience as a founder, founding engineer, or early engineer at a startup.
• Experience building workflow, orchestration, event-driven, or distributed systems.
• Experience developing platforms or reusable infrastructure for other engineers.
• Experience building or deploying AI and LLM-powered products.
• Familiarity with enterprise integrations, APIs, data pipelines, and systems of record.
• Experience working in complex industries such as financial services or healthcare.