Senior Full Stack Engineer

Arcus Search; San Francisco (CA); On-site; USD 180,000 - 280,000; Full time

Job summary

Arcus Search is hiring a Senior Full Stack Engineer to own technical decisions and shape the engineering foundations of an early-stage AI startup. You will work across the full stack, building production-grade applications that integrate LLMs into enterprise workflows and collaborate with a small, ambitious team.

You’ll contribute from architecture to deployment, engaging with customers to understand challenges and iterate the product.

Qualifications

• 5+ years of software engineering experience with full-stack focus.
• Experience integrating LLMs into production apps.
• Backend in Go or other typed language plus Python.
• Frontend with React and TypeScript; PostgreSQL knowledge.
• Understanding of LLM development patterns: orchestration, tool calling, context management.
• Experience owning significant engineering projects and decisions.
• Product-minded approach with balance of quality and delivery speed.
• Strong communication and incorporating customer feedback into product development.
• Experience with agentic AI or multi-step workflows.
• Prior startup or founding engineer experience.
• Experience in large tech environments with high autonomy.
• Familiarity with Terraform, Docker, and GCP.

Responsibilities

• Design, build and ship production features across frontend, backend and AI integration layers.
• Develop LLM-powered applications with orchestration and tool calling.
• Build reliable backend services and APIs using Go, Python and PostgreSQL.
• Take ownership of projects end-to-end, guiding architecture and delivery.
• Work with customers to understand challenges and iterate based on feedback.
• Help establish engineering practices and technical foundations as the company grows.

Skills

Full-stack development

LLM integration

Go

Python

React

TypeScript

PostgreSQL

LLM patterns

Project ownership

Product-minded

Communication

Agentic AI

Startup experience

Large tech experience

Infrastructure as code

Tools

Terraform

Docker

GCP

Job description

San Francisco / New York | $180,000-$280,000 + Equity | On-site

I'm working with an early-stage AI startup building technology at the intersection of enterprise process intelligence and agentic AI.

Backed by leading venture capital investors, the company is developing a platform that helps some of the world's largest organisations capture, understand and operationalise their internal processes through AI. The business is already working with enterprise customers and is looking to expand its engineering team as it scales.

They're now looking for a Senior Full Stack Engineer to play a key role in building the product, owning technical decisions and shaping the engineering foundations of the business.

The opportunity

You’ll work across the full stack, building production-grade applications that integrate LLMs into real enterprise workflows. This is an opportunity to join a small, ambitious engineering team where you’ll have meaningful ownership, direct customer exposure and the ability to influence product direction from an early stage.

You’ll be involved in everything from architecture and implementation to deployment, customer feedback and continuous iteration.

What you’ll be doing

• Design, build and ship production features across the frontend, backend and AI integration layers.
• Develop LLM-powered applications, including orchestration, tool calling, context management and multi-step workflows.
• Build reliable backend services and APIs, working with Go, Python, PostgreSQL and modern frontend technologies.
• Take ownership of projects end-to-end, making pragmatic technical decisions around architecture, scalability and delivery.
• Work closely with customers to understand their challenges, gather feedback and improve the product based on real-world usage.
• Help establish engineering practices and technical foundations as the company grows.

What they're looking for

• 5+ years of software engineering experience, ideally with a strong full-stack background.
• Experience building and shipping production applications that integrate LLMs or other AI capabilities.
• Strong backend engineering skills in Go or another typed language, alongside Python experience.
• Experience with React and TypeScript, plus PostgreSQL and production database operations.
• An understanding of modern LLM development patterns, such as orchestration, tool calling, context management and evaluations.
• Experience owning significant engineering projects and making decisions independently.
• A pragmatic, product-minded approach, with the ability to balance engineering quality against delivery speed.
• Strong communication skills and experience incorporating customer feedback into product development.
• Experience with agentic AI, AI agents or multi-step automated workflows.
• Previous experience at an early-stage startup or as a founding engineer.
• A combination of experience in larger technology companies and high-autonomy environments.
• Familiarity with Terraform, Docker, GCP or infrastructure as code.
• Experience building enterprise SaaS products.

What's on offer?

• The opportunity to join a venture-backed AI business at an early stage.
• Significant ownership over product development, architecture and technical direction.
• Direct exposure to enterprise customers and real-world AI implementation challenges.
• A small, ambitious team where engineers can have a tangible impact on the company's trajectory.
• On-site working five days per week in San Francisco or New York.

Visa support is available for eligible candidates, including H-1B transfers, STEM OPT and TN visas.