Senior Full Stack Engineer (AI Platform)

Job Description

Protagonist is seeking a Senior Full Stack Engineer (AI Platform) to help build and evolve our internal AI-powered platform. This role is designed for an experienced engineer who can own production systems end-to-end—from backend services and data infrastructure to intuitive, analyst-facing applications—and who is excited to apply modern AI capabilities within a robust software platform.

The ideal candidate is a strong full-stack engineer first, with experience building AI- and LLM-powered applications in production. You are comfortable working across the stack, making pragmatic architecture decisions, and taking ownership from technical design through deployment. You thrive in a fast-paced, small-team environment, are comfortable navigating ambiguity and complex technical problems, and bring the judgment and experience to help raise the bar for the engineers around you.

Reporting to the VP of Technology, you will design and build core applications and services that power our platform, partnering directly with technical leadership to shape product and architectural direction. You will also collaborate with our customer-facing team to translate analyst and customer needs into scalable, reliable software.

Responsibilities

• Own features end-to-end across the platform: Django REST APIs and data models, React/TypeScript UI, workflow pipelines, and LLM agent services, from technical design through coding, testing, and production
• Partner with technical leadership on architecture and roadmap: turn product vision into system designs, pressure-test ideas, and help drive the technical direction of the platform
• Build LLM-powered systems on AWS Bedrock: tool-using agents, RAG retrieval over OpenSearch, prompt engineering, evaluation, and cost/usage controls
• Develop data and ML workflows in Metaflow orchestrated on Argo Workflows/Kubernetes: ingestion, enrichment, classification, and document processing at scale
• Design for the whole system: PostgreSQL schema, OpenSearch indexing and search, event-driven processing (Kafka, Redis/Celery), and clean API contracts between services
• Collaborate with the customer-facing team to create solutions that support customer needs
• Work in agile sprints with the engineering team, making informed decisions between competing solutions

Requirements

• U.S. person eligible to work on government contracts; active or prior SECRET clearance preferred
• Bachelor’s and 5 years of experience, or master’s degree and 3 years of experience, in Computer Science, Computer Engineering, or a related technical field
• 5+ years building production software, with demonstrated ownership of full-stack systems
• Expert-level Python, with deep Django (or equivalent framework) and PostgreSQL experience
• Strong TypeScript/React skills, comfortable building complex, data-heavy interfaces
• Experience building LLM applications: agents, tool calling, RAG, prompt engineering, and evaluation against hosted model APIs (e.g., AWS Bedrock)
• Experience with search infrastructure (OpenSearch/Elasticsearch) and event-driven architectures (Kafka, Celery/Redis, or similar)
• Hands-on with AWS, Docker, Kubernetes, Git, and CI/CD; comfortable reading and modifying Terraform

Ideal Candidates

• Experience with ML/data orchestration (Metaflow, Argo, Airflow) or NLP pipelines
• Experience in compliance-constrained environments
• Experience with data visualization and analyst-facing tools
• Startup instincts: bias to ship, comfortable with ambiguity

Join Us

If you’re passionate about technology and making an impact, apply today! Protagonist is dedicated to fostering a welcoming and innovative environment where everyone’s voice can make a difference.

Protagonist is an Equal Opportunity Employer.

Salary Range: $95,000-$141,000 based on education and level of relevant experience.

Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.