Senior Software Engineer | Full-Stack | Applied AI

Senior Software Engineer | Applied AI | Full-Stack | San Francisco

Salary: $180K - $220K + equity | Onsite

Location: San Francisco (paid relocation available for candidates currently living elsewhere in the US)

Why Join Them: Well-funded ($15M+) early-stage startup with rapid traction, developing an AI-driven platform that optimises growth marketing at scale, automating complex workflows. Small, high-performing team with ambitious expansion plans.

Required Sector Experience: 3 - 6 years of applied AI engineering experience, ideally with multi-agent systems or AI orchestration projects.

Please only apply if you meet this and all of the requirements above and below:

• Candidate must be currently living in the USA and legally able to work.
• Proven experience building reliable AI-enabled systems in production (applied AI, not research).
• Hands-on full-stack experience, delivering features end-to-end in Python, TypeScript, or similar stacks.
• Familiar with multi-agent systems, Langchain or Semantic Kernel, and LLM applications.
• Comfortable working 0→1 in a startup environment, shaping product and engineering practices.
• Strong communication skills and a customer-focused mindset.

The Opportunity

Optimal has partnered with a stealth-mode startup who is solving the hardest parts of growth marketing using AI. Their platform executes high-quality campaigns at scale, delivering measurable results faster and more reliably than traditional methods.

You’ll join a small, high-caliber engineering team, working across the stack to architect, build, and iterate on AI systems that directly influence customer outcomes.

The Role

• Architect, evaluate, and optimise complex AI/NLP systems end-to-end.
• Build and iterate multi-agent AI architectures in production.
• Collaborate closely with product and design to integrate AI seamlessly.
• Rapidly prototype and deliver features with high reliability and quality.
• Work across frontend (React/NextJS/TypeScript) and backend (Python, C#, Postgres) as needed.
• Shape engineering culture in a fast-moving, early-stage team.

Who We’re Looking For

• 2–6 years experience in applied AI with strong understanding of LLM capabilities and limitations.
• Experience building multi-agent systems or AI orchestration pipelines.
• Hands-on full-stack experience: Python backend, React/TypeScript frontend, GraphQL, and cloud deployment (Google Cloud).
• Thrives in ambiguity, ownership, and fast-paced early-stage environments.
• Passionate about quality-first engineering, building reliable and scalable AI products.
• Computer Science degree preferred

Why This Role

• Cutting-edge AI work: Build AI systems that deliver outcomes at scale, not just demos.
• Well-funded and high-growth: $15M+ raised, with rapid traction and ambitious expansion plans.
• First-mover advantage: Be part of the first team automating complex marketing workflows with AI.
• In-person culture & flexibility: Energetic San Francisco office with paid relocation for US-based candidates.
• Quality-focused engineering: Work in a team that values reliability, craftsmanship, and impact.
• Great benefits package: Competitive salary, equity, unlimited PTO, offsites, health coverage, and education stipends.

If this sounds like you and you want to be part of something special, reach out to us for a prompt response.