Platform Engineer, Horizon: Build Long-Horizon AI Agents

RiseMe; San Francisco (CA); On-site; USD 180,000 - 240,000; Full time

Benefits offered by this job

Flexible (unlimited) paid time off

Medical, dental, and vision benefits

Life insurance and disability benefits

Retirement plan dependent on country

Parental leave

Fertility and family building

Lunch, snacks and coffee

Discretionary benefit stipend

Free alphorn lessons

Job summary

Sierra in San Francisco is seeking a Senior Platform Engineer to build the core systems for long-horizon AI agents. You will create feedback loops, memory, signals, and a scalable orchestration layer that supports multi-channel engagement.

You will turn 0-to-1 work into durable product capabilities, collaborate with product and engineering to shape Horizon’s architecture and roadmap, and help hand off successful deployments for ongoing use.

Qualifications

• Experience building and scaling production systems.
• Strong platform and systems engineering fundamentals.
• Ability to move between customer problems, product design, and technical implementation.
• High technical judgment in fast-changing environments.
• Builder mindset with end-to-end delivery experience.

Responsibilities

• Build primitives for self improvement: feedback loops, memory, signals, and decisioning infrastructure.
• Design and ship long-horizon agents across channels (voice, SMS, email).
• Turn 0-to-1 work into a reusable platform and tools.
• Address complex orchestration, data, observability, and integrations.
• Collaborate with product/engineering to shape Horizon’s architecture and roadmap.
• Translate validated solutions into durable product capabilities.

Skills

End-to-end production systems

Platform engineering

Technical judgment

Builder mindset

Customer collaboration

Adaptability

Communication

2+ years software engineering

Python

TypeScript

Go

React

Job description

Sierra in San Francisco is seeking a Senior Platform Engineer to build the core systems for long-horizon AI agents. You will create feedback loops, memory, signals, and a scalable orchestration layer that supports multi-channel engagement.

You will turn 0-to-1 work into durable product capabilities, collaborate with product and engineering to shape Horizon’s architecture and roadmap, and help hand off successful deployments for ongoing use.