Principal AI Architect

HopHR; San Francisco (CA); Hybrid; USD 150,000 - 200,000; Full time

Job summary

HopHR is looking for a Principal Engineer in San Francisco to define and own the architectural vision for next-generation AI systems. The role requires a minimum of 5 years in AI/ML engineering, including at least 2 years in a leadership capacity. Responsibilities include prototyping breakthrough AI capabilities and establishing technical foundations for data architecture. Candidates should have a strong research background, original AI systems development experience, and must be authorized to work in the US without sponsorship.

Qualifications

• 5+ years in AI/ML engineering with at least 2 years in a principal or lead architect role.
• Deep expertise in LLM training, agentic design, and knowledge graph construction.
• Strong history of building original AI systems with market success.

Responsibilities

• Define and own architectural vision for next-generation AI systems.
• Prototype and evaluate breakthrough AI capabilities.
• Set technical foundations for data architecture and inference infrastructure.

Skills

AI/ML engineering

Architectural vision

Large-scale data modeling

LLM training and fine-tuning

Greenfield conditions

Education

BS/MS/PhD in Computer Science, AI/ML

Tools

Proprietary model development

Data architecture

Job description

Draup is a Series A-funded agentic AI company building the intelligence layer for how global enterprises make workforce and go-to-market decisions. We work with 250+ enterprise clients — including 5 of the Fortune 10 — processing 1B+ job descriptions, 850M+ professional profiles, and signals from 100+ labor databases.

We are now building our Silicon Valley engineering team — a small, senior group focused on next-generation AI research and product.

Location: San Francisco, SoMa — Hybrid: minimum 3 days in office per week, 2 days flexible.

What you’ll do

• Define and own the architectural vision for next-generation AI systems: novel agent architectures, reasoning systems, and proprietary model development.
• Prototype and evaluate breakthrough AI capabilities — predictive modeling, autonomous signal synthesis, multi‑modal intelligence — that create defensible IP.
• Set the technical foundations: data architecture, model serving, agent orchestration, and inference infrastructure for a multi-year product horizon.
• Evaluate and adopt emerging AI paradigms (multi‑agent reasoning, RLHF, retrieval‑augmented fine‑tuning) before they are mainstream.
• Establish engineering standards, architecture review processes, and IP documentation practices for the team.

What we require

• BS/MS/PhD in Computer Science, AI/ML, or related field. PhD or equivalent research depth preferred.
• 5+ years in AI/ML engineering with at least 2 years in a principal engineer or lead architect role.
• Demonstrated history of building original AI systems that became products — not implementations of existing patterns.
• Deep expertise across: LLM training and fine‑tuning, agentic system design, knowledge graph construction, large‑scale data modeling.
• Comfort operating in greenfield conditions: high ambiguity, high ownership.
• Patents, published research, or shipped products with clear proprietary differentiation are strong signals.
• No visa sponsorship. Must be authorized to work in the US without current or future employer sponsorship.