Founding Technical Staff – AI Systems & Platforms

Lightsage; San Francisco (CA); On-site; USD 140,000 - 210,000; Full time

Job summary

Lightsage is hiring an early-stage engineer in San Francisco to own systems end-to-end across frontend, backend, infrastructure and data. You’ll work directly with customers to turn problems into shipped features and contribute to rapid product iteration with AI coding tools.

As one of the first engineers, you’ll shape architecture, collaborate with the founding team, and build scalable solutions that power enterprise integrations. This demanding, on-site role offers strong ownership and growth.

Qualifications

• Track record of taking a loosely defined customer or product problem to a shipped solution with little direction.
• Strong backend experience building reliable systems that handle production load.
• Hands-on experience shipping quickly with AI coding tools such as Claude Code or Codex.
• Clear thinking about technical trade-offs, and clear written communication.
• Experience doing research or running rigorous experiments, such as LLM evals, benchmarks or A/B tests, and drawing sound conclusions from noisy results is a plus.
• Experience with Next.js, FastAPI, Supabase or Microsoft Azure is a plus.
• Prior founder or early-stage startup experience is a plus.

Responsibilities

• Own end-to-end systems across frontend, backend, infrastructure and data.
• Work directly with customers to translate their problems into shipped features.
• Develop and run experiments/benchmarks to measure impact on guidance quality.
• Build agents and benchmarks to improve recommendations and reliability.
• Scale evaluation and data pipelines for enterprise customers.

Skills

Backend systems

AI tooling usage

Clear written communication

Experimentation & A/B testing

Customer collaboration

Tools

Next.js

FastAPI

Supabase

Microsoft Azure

Job description

Lightsage is hiring an early-stage engineer in San Francisco to own systems end-to-end across frontend, backend, infrastructure and data. You’ll work directly with customers to turn problems into shipped features and contribute to rapid product iteration with AI coding tools.

As one of the first engineers, you’ll shape architecture, collaborate with the founding team, and build scalable solutions that power enterprise integrations. This demanding, on-site role offers strong ownership and growth.