Staff Frontend Engineer

HASH is an open-source platform dedicated to improving decision‑making through knowledge capture, modeling tools, and distributed simulation of complex systems. Committed to eliminating information failure, HASH empowers individuals and organizations to make informed, effective decisions.

Role Description

Responsibilities

Day‑to‑day, you’ll:

• Design, build, and ship production‑ready React/TypeScript components and app‑wide features for complex data‑driven UIs
• Work with mathematical experts to convert world‑modeling theory formalizations into software requirements, and write tests which ensure implementation correctness
• Convert novel UX/UI designs— for new world‑modeling and AI‑interaction features — into performant, responsive and accessible experiences that work across devices
• Establish project‑wide standards for code quality (e.g. via linting), review and testing, and provide feedback on the work of other frontend engineers
• Profile and optimize rendering performance for complex interactions and visualisations
• Tell the story of best practices and lessons learned in developing and testing novel, complex world‑modeling interfaces, e.g. via blog posts and workshops
• Partner with backend/infra teams to identify and manage interdependencies, and to help define robust APIs that support excellent, feature‑rich frontend performance

Requirements

• Expertise with React, TypeScript, modern HTML & CSS
• Proven track record architecting and delivering rich web apps that involve complex user interactions
• Rigorous approach to documenting and versioning components for external audiences
• Experience profiling and debugging performance in devtools
• Comfortable taking a visible technical leadership role, mediating discussions around standards and implementation approaches, and taking accountability for the delivery of features on time and to spec
• Excellent written & verbal communication in English and comfort working async

Nice‑to‑haves

• Familiarity with process/model‑oriented UIs: BPMN, UML, systems‑dynamics models, graphs, etc.
• Understanding of WCAG 2.2 and pragmatic accessibility techniques (ARIA, focus management, keyboard UX)
• Public record of maintaining a well‑documented, semantically versioned library (ideally in an open‑source context)
• Experience with CRDTs or other real‑time collaboration solutions
• Hands‑on experience with WebAssembly pipelines
• Canvas/WebGL experience for high‑performance rendering

About this role

We offer leading compensation, including competitive salaries and tax‑advantaged stock options. We also provide:

• Employer pension contributions
• At least 30 days paid holiday
• Twice‑yearly in‑person team retreats around the world

HASH's founders have previously sold companies for tens of millions, hundreds of millions (Trello; $425m) and billions of dollars (Stack Overflow; $1.8 billion).

In this role you’ll work directly with the Founder of HASH. This role is a full‑time, in‑office position in Berlin.