Senior Full Stack Engineer

Rational Dynamics builds customized AI reasoning systems for tasks of high cognitive complexity.

Our initial market is the world’s leading institutional asset owners. We work very closely with these customers to create specialized, rigorous benchmark datasets encompassing their most valuable and difficult knowledge work. Then we use the benchmarks to construct agentic large reasoning models, applying the same rigor to prove that the models correctly do the work. Customers access the models through a tailored application service, making their most skilled, expensive workers dramatically more productive.

We are an early-stage startup. Our founders previously started Voleon, now one of the world’s largest systematic investment managers, and recognized as a longstanding industry leader in applied machine learning. They bring to Rational Dynamics the same research discipline and data-driven focus that succeeded in the unforgiving, high-stakes setting of financial markets.

We are looking for entrepreneurial researchers and engineers who want to work on cutting edge agentic AI methods and build out a best-in-class core technical infrastructure. Our work environment is highly collaborative. Your colleagues will be accomplished experts in AI/ML, statistics, and systems engineering.

As a Senior Full Stack Engineer, you’ll join a group of founding engineers building the application layer for an AI product used by global financial asset owners in high-stakes environments, including customer-facing interfaces, backend orchestration, and integrations that connect customer data. You'll design data-rich UIs for complex investment workflows, build APIs that keep AI agents reliable in production, and ship features end-to-end with detail and execution. The role is frontend-leaning, but full stack in practice.

This role requires frontend depth combined with backend competence, product thinking, and customer empathy. You'll work with PhD researchers and a proven executive team on novel problems. You need to be comfortable in ambiguity, technical enough to ship across the stack, and care about UI craft.

The right person enjoys building user-facing software, sweats the details, and wants to see their work change how billion-dollar decisions get made.

• Own, extend, and improve production of full stack systems. This includes user interfaces, APIs contracts, and backend services that deliver reliably to customers

• Develop and improve responsive user-facing interfaces that surface complex AI outputs

• Ensure frontend features are production-ready and resilient to edge cases

• Partner with product stakeholders to establish and evolve the design systems and UI toolkit

• Design and implement APIs that connect the platform to client environments and data sources, with a focus on reliability and ease of integration

• Build and maintain integration points with data ingestion pipelines, providing the structure and feedback mechanisms that allow our agents to perform effectively in customer environments

• Collaborate with ML and infrastructure teams to integrate AI capabilities into product features that customers can depend on

• Drive features from problem identification through deployment and iteration, building in mechanisms to capture customer feedback and continuously improve the product

• Continuously improve performance, reliability, and user experience across the stack

• Lead adoption of agentic development tools and agentic software development practices

• 5+ years of experience building and shipping full stack applications in production

• Strong proficiency in a modern frontend framework (React or similar) specializing in component architecture and refined UX

• Competence in backend language (Python, Rust, or Node) and command of REST design principles

• Strong customer-centric intuition focused on usability, accessibility, and product quality

• Comfort operating on a small team with dynamic requirements and strong ownership mentality

• Experience with data pipeline tooling or familiarity with data ingestion workflows

• Exposure to fintech products or enterprise B2B software

• Prior early-stage or small-team experience where you owned product and technical decisions end-to-end

We expect that strong candidates won’t necessarily meet every qualification above. If most of this resonates and the gaps feel learnable, we’d rather hear from you than not.

If you have a great candidate in mind for this role and would like to have the potential to earn $7,500 to $15,000 if your referred candidate is successfully hired and employed by Rational Dynamics, please use this form to submit your referral. For more details regarding eligibility, terms and conditions please make sure to review the Rational Dynamics Referral Bonus Program.

Rational Dynamics is an Equal Opportunity employer. Applicants are considered without regard to race, color, religion, creed, national origin, age, sex, gender, marital status, sexual orientation and identity, genetic information, veteran status, citizenship, or any other factors prohibited by local, state, or federal law.