Senior Machine Learning Engineer

Job Description

Protagonist is looking for a Senior Machine Learning Engineer who builds production-ready systems for mission-critical work. You bring strong engineering discipline, systems thinking, and a bias toward scalable, well-architected solutions—owning the full ML lifecycle from design to deployment. 

You're a builder and strategic partner across engineering, product, and client-facing teams, expanding what AI can do at Protagonist. You stay curious and current with advances in ML, infrastructure, and software development. 

Responsibilities

• Partner with product, engineering, and data science teams to identify high-impact NLP use cases and turn business needs into ML solutions that deliver measurable value 
• Own production NLP pipelines spanning narrative detection, NER, span classification, stance and characterization analysis, event extraction, deduplication, and knowledge-base entity linking over multi-language, noisy real-world text 
• Design, build, and operate production NLP pipelines, narrative detection, event classification, entity resolution and linking, deduplication — over multi-language, noisy real-world text at scale 
• Build and maintain ML workflows in Metaflow orchestrated on Argo Workflows and Kubernetes (EKS), including GPU-accelerated training and batch inference 
• Develop LLM-powered features on AWS Bedrock: RAG pipelines with vector search on OpenSearch, tool-using agents, and document-analysis workflows — within GovCloud/ITAR constraints 
• Fine-tune and deploy transformer models (classification, embeddings, entity linking) for domain-specific and foreign-language content 
• Establish ML evaluation frameworks regression testing, hallucination detection, quality metrics and define success criteria with product managers 
• Integrate ML services into our Django/PostgreSQL platform and event-driven infrastructure (Kafka, Redis, OpenSearch) 
• Lead technical discussions to align cross-functional teams on ML strategy, architecture, and implementation 
• Mentor others, share knowledge, and help evolve ML practices—balancing innovation with practical delivery 

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, Machine Learning, or a related technical field 
• Proven track record building and deploying production ML systems, with deep NLP expertise (transformers, LLMs, embedding models) 
• Strong Python skills and fluency with PyTorch and the Hugging Face ecosystem 
• Hands-on experience with AWS (GovCloud experience a strong plus), Kubernetes, Docker, Terraform, and CI/CD pipelines 
• Experience with ML orchestration and experiment tracking (e.g., Metaflow, Argo Workflows, MLflow, or similar) 
• Experience with vector search and document indexing (OpenSearch/Elasticsearch or similar) 
• Experience building LLM applications,  RAG, agents, prompt engineering, and evaluation 
• Skilled at scaling ML for multi-modal (text, image, video) and domain-specific applications, and working effectively across engineering, product, and business teams 

Ideal Candidates 

• Experience integrating ML into full-stack products (Django/REST APIs, React frontends) or decision-support tools 
• Experience operating in compliance-constrained environments 
• Strong communicator and cross-functional collaborator 
• Self-starter who thrives in ambiguity and startup-like environments 

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.