Software Engineer, Horizon

Sierra · San Francisco, CA · $230K – $390K · Engineering

Posted 2026-09-25

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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.

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