Platform Engineer for AI Agents & Horizon

Sierra; San Francisco (CA); Hybrid; USD 180,000 - 240,000; Full time

Benefits offered by this job

Flexible PTO

Medical, dental, vision benefits

Life insurance and disability

Retirement plan

Parental leave

Fertility and family benefits

Meals and snacks

Job summary

Sierra is the leading platform for customer-facing AI agents, headquartered in San Francisco. We are seeking engineers who can build end-to-end production systems and craft reusable platform primitives for long-horizon agents across voice, SMS, and email channels.

You’ll collaborate with product and customers to define architecture, deliver scalable solutions, and guide these efforts from concept to durable product.

Qualifications

• Experience building and scaling end-to-end production systems.
• Strong platform and systems engineering fundamentals.
• Ability to move between customer problems, product design, and technical implementation.
• Strong technical judgment in ambiguous, fast-changing environments.
• A builder’s mindset with 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.

Responsibilities

• 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 define architecture and roadmap.
• Create a clean path beyond the POC: translate what you built into durable product capabilities and enable deployment.

Skills

End-to-end systems

Platform engineering

Customer interaction

Technical judgment

Communication

Python/TypeScript/Go

Job description

Sierra is the leading platform for customer-facing AI agents, headquartered in San Francisco. We are seeking engineers who can build end-to-end production systems and craft reusable platform primitives for long-horizon agents across voice, SMS, and email channels.

You’ll collaborate with product and customers to define architecture, deliver scalable solutions, and guide these efforts from concept to durable product.