Full Stack Software Engineer (React + Python)

We're looking for a Full Stack Software Engineer to join an ambitious project at the intersection of scientific computing, causal AI, and collaborative software.

You'll help build a next-generation platform that enables scientists and engineers to collaboratively create, validate, and simulate causal probabilistic models in real time. Think of a real-time collaborative workspace for advanced scientific modeling, where users can ingest data, fit models, run counterfactual simulations, and visualize results through an intuitive interface.

This role requires someone who enjoys solving complex technical problems, working across the full stack, and collaborating with a highly technical research team while maintaining a high degree of autonomy.

What You'll Do

• Design and build new product capabilities across both frontend and backend.
• Integrate existing Python scientific libraries into a production web application.
• Develop features for data ingestion, processing, storage, and visualization.
• Build interfaces for model validation, prediction analysis, and performance metrics.
• Implement automated model fitting workflows.
• Develop user experiences for running and visualizing causal and counterfactual ("what-if") simulations.
• Improve real-time collaborative functionality across the application.
• Work closely with researchers to transform advanced modeling capabilities into intuitive product features.

What We're Looking For

The ideal candidate will have the following profile:

• Degree in Computer Science, Engineering, or related field.
• 5+ years of professional software engineering experience.
• Strong experience with React and TypeScript, including modern tooling (Vite, pnpm) and client-side routing.
• Solid Python development experience, ideally with FastAPI and Pydantic.
• Experience designing and consuming REST APIs.
• Comfort with modern state and data-fetching patterns (TanStack Query, Jotai, Redux, or equivalents).
• Experience with component libraries and utility-first CSS (MUI, Tailwind, or similar).
• Testing discipline across unit and end-to-end layers (Vitest, Testing Library, Cypress, Playwright, or equivalents).
• AWS experience, including managed authentication services such as Cognito.
• Ability to work independently with minimal supervision.
• Strong communication skills in Spanish and English.

Bonus points for:

• Experience with real-time collaborative applications.
• Experience with WebSockets.
• Experience building data-intensive applications.
• Experience with graph or canvas-based interfaces (React Flow / xyflow or similar).
• Experience with OIDC and JWT-based authentication flows.
• Experience with scientific computing, data visualization, or machine learning applications.
• Familiarity with probabilistic modeling or causal inference is a plus.

Benefits

• Fully remote work
• Fixed monthly compensation in USD
• Full-time, long-term contract
• Paid Time Off (PTO) & Paid Local National Holidays

About Marsie

Marsie is a technology partner that provides experienced software engineers to help companies with their product and platform development. We operate on a staff augmentation model, embedding experienced engineers into our clients’ teams to deliver immediate impact, strong technical skills, and a collaborative mindset. Our engineers work on complex systems across modern stacks and cloud environments, while enjoying a remote culture built on trust and long-term relationships.

About the Client

Our client is a world-class research organization developing cutting-edge technologies at the intersection of AI, scientific computing, and advanced engineering. Their multidisciplinary teams build innovative software platforms that enable researchers to solve complex real-world problems through data-driven modeling and simulation.