Founding Engineer (Full Stack)

davidjoseph-co; San Francisco (CA); On-site; USD 180,000 - 230,000; Full time

Job summary

davidjoseph-co is hiring a true full-stack founding engineer for a seed-stage startup in San Francisco. You’ll work directly with the technical founder across the conversational AI agent, the embeddable customer-facing experience, the internal platform, the evaluation and self-improvement pipeline, and the underlying infrastructure.

This on-site role offers rapid impact, equity, and broad scope across agents, product, evals, and infrastructure as the first engineers join the team.

Qualifications

• 1–5 years building full-stack products at a venture-backed B2B SaaS startup with real paying customers.
• Genuinely full-stack with strong front-end, UX, and customer-facing product experience.
• Hands-on experience shipping production AI-agent features to real users (LLM agents, RAG pipelines, or agent orchestration).
• Comfortable working with React and Python.
• CS undergraduate degree.
• Thrives in ambiguous, fast-moving environments and takes ownership.
• Strong product instincts with ability to turn feedback into shipped code.

Responsibilities

• Diagnose and fix live customer agents, then ship fixes to the orchestration layer the same day.
• Prototype generative UI that adapts in real time to what each prospect cares about.
• Own an eval pipeline: catch quality regressions, trace root causes, roll back, and add tests.
• Design and build net-new infrastructure (e.g. versioning so customers can preview agent changes before they go live).
• Move across the stack as the problem requires, including CSS, migrations, and customer debugging.

Skills

Full-stack

React

Python

UX/product mindset

Ownership

Education

CS undergraduate degree

Job description

San Francisco, CA · On-site · Full-time
Compensation: $180K–$230K + equity

About the Company

Our client is a seed-stage startup building conversational AI agents that run live product demos and autonomous sales for B2B companies — prospects start a conversation and get an instant, interactive demo instead of waiting on a scheduled call. They’ve tripled their customer base in the past month and are backed by strong investors. You’d be one of the first engineers on the team, working directly with the technical founder.

Founded 2025 · Small founding team · Industry: B2B, AI, Software Development

The Role

This is a true full-stack founding role with no fixed lane. You’ll build across the entire product alongside the technical founder — the conversational agent, the embeddable customer-facing experience, the internal platform, the evaluation and self-improvement pipeline, and the infrastructure underneath it. You’ll usually get a problem statement rather than a spec and own the solution end to end, shipping quickly and iterating in production.

What you’ll be doing

• Diagnose and fix live customer agents, then ship fixes to the orchestration layer the same day
• Prototype generative UI that adapts in real time to what each prospect cares about
• Own an eval pipeline: catch quality regressions, trace root causes, roll back, and add tests
• Design and build net-new infrastructure (e.g. versioning so customers can preview agent changes before they go live)
• Move across the stack as the problem requires, including the unglamorous work — CSS, migrations, and customer debugging

Tech stack: Python, React

Requirements

• 1–5 years building full-stack products at a venture-backed B2B SaaS startup (roughly pre-seed through Series C) with real, paying customers
• Genuinely full-stack, with strong front-end, UX, and customer-facing product experience — not backend-only
• Hands-on experience shipping production AI-agent features to real users: LLM agents, RAG pipelines, or agent orchestration (frameworks or custom-built)
• Comfortable working with React and Python
• A CS undergraduate degree
• Thrives in ambiguous, fast-moving environments and takes high ownership
• Strong product instincts, with genuine excitement about turning user feedback into shipped code

Nice to Haves

• Prior experience at a venture-backed sales-tech startup

Why Join

• Founding-team seat with direct access to the technical founder, helping set engineering culture from the ground up
• Real, fast-growing customer traction and strong backing
• Broad scope across agents, product, evals, and infrastructure — the hard problems, not a narrow slice

Details

• Location: San Francisco, CA
• Work policy: On-site, 5 days a week
• Compensation: $180K–$230K + equity
• Visa sponsorship: Not available (US citizens or Green Card holders)
• Employment type: Full-time