Senior AI Agent Engineer: Scale Production Systems

Hackajob Ltd; Greater London; On-site; GBP 90,000 - 110,000; Full time

Benefits offered by this job

Medical, dental, and vision benefits

Life insurance and disability benefits

Retirement plan

Equity plans

Job summary

Were Sierra is building a platform that helps businesses create better, more human customer experiences with AI. Were a primarily in-person company based in San Francisco, with offices in London and other cities worldwide.

The founders have led roles at major tech companies, and the culture centers on trust, customer obsession, craftsmanship, intensity, and family. We offer full-time roles with benefits including medical, dental, vision, life insurance, disability, retirement plans, equity

Qualifications

• Experience building and scaling end-to-end production systems.
• Strong technical problem-solving skills in fast-changing environments.
• A builders and tinkerers mindset with high agency.
• Comfort working directly with customers to understand needs.
• Excellent communication with technical and non-technical audiences.
• Preferred: Experience building or deploying AI/LLM systems in production.
• Preferred: Founder or founding engineer experience balancing craft, ownership and speed.
• Preferred: Familiarity with AI agent tools and techniques (evaluation frameworks, agent tooling, RAG pipelines, prompt engineering).
• Preferred: Prior experience with React, TypeScript, and/or Go.
• Preferred: Experience interfacing with customers or leading technical projects with external stakeholders.

Responsibilities

• Design and deliver highly performant, reliable, intuitive, production-grade AI agents that support growth and scale across industries.
• Own the Agent Development Life Cycle from pilot to deployment and continuous iteration.
• Work directly with enterprise leaders to understand business challenges and build AI agents that transform operations at scale.
• Partner with startups in London to embed AI agents across their business stacks.
• Use customer work to identify unmet needs and collaborate with research, product, and platform teams.
• Design agents for telecommunications and media companies, including churn management and complex interactions.
• Develop generalizable AI agent frameworks for industry-specific use cases.
• Facilitate design partnerships for product initiatives and new architectures.
• Experiment with voice models and enterprise-scale integration.

Skills

End-to-end production systems

Technical problem solving

Owner mindset

Customer interaction

Communication skills

AI/LLM in production

Founder/founding engineer experience

AI agent tools

React

TypeScript

Go

Customer-facing projects

Tools

React

TypeScript

Go

Salesforce

VR

Job description

Were Sierra is building a platform that helps businesses create better, more human customer experiences with AI. Were a primarily in-person company based in San Francisco, with offices in London and other cities worldwide.

The founders have led roles at major tech companies, and the culture centers on trust, customer obsession, craftsmanship, intensity, and family. We offer full-time roles with benefits including medical, dental, vision, life insurance, disability, retirement plans, equity