Senior Frontend Engineer
Hybrid (New York City)
Unlocking human performance, safety and health
through circadian timing and control
Time isn’t just hours, minutes, and seconds. There’s a different kind of time — not invented by us or powered by batteries. It’s each person’s internal circadian time, which quietly governs nearly every biological system in our bodies — from sleep and alertness to metabolism and immune function — and can vary significantly between people.
The undisputed leader
in circadian technology
At Timeshifter, we translate complex circadian science into practical, high-impact products that address challenges affecting billions, each using the same core technology. Our first product — a jet lag app — is now the most downloaded in the world. Our second is designed to help shift workers improve sleep, health, and quality of life, while enhancing safety and boosting productivity. Timeshifter is also trusted where circadian control is mission-critical, from space missions to elite sports. As we enter the next frontier of personalized medicine, we’re exploring how Timeshifter can serve as the clock for delivering healthcare aligned with each person’s biology.
Role overview:
As a Senior Frontend Engineer, you will lead the development of Timeshifter’s iOS, Android, and web applications. Working closely with our co-founder and CXO, Jacob Ravn, you will shape the user experience and bring new features to life at the intersection of circadian science, behavior change, and technology.
What you will do:
Build highly responsive, beautiful, and high-performing frontend experiences across mobile and web.
Translate pixel-perfect designs into functional interfaces across all screen sizes and devices.
Work closely with design and product teams to expand our feature set and improve UX.
Integrate with backend systems and third-party APIs.
Contribute to architectural decisions and set high engineering standards.
Push boundaries with custom animations, transitions, and interactions.
This is a pivotal role that directly impacts millions of lives by redefining how circadian science addresses health, safety, and performance challenges.
At Timeshifter, you will be part of a passionate, collaborative team dedicated to advancing circadian science. At Timeshifter, we value innovation, work-life balance, and making a real-world impact. We offer flexible working arrangements and the opportunity to grow into a leadership role within a fast-growing company.
Timeshifter is committed to building an inclusive team and encourages candidates from all backgrounds and experiences to apply. Diversity drives our innovation.
Requirements:
A passion for precision — in code, design, and user experience.
Deep expertise in CSS and responsive design principles.
Expert-level knowledge of JavaScript as a real programming language.
Strong experience with React, AngularJS, or similar client-side frameworks.
Fluency in Web Animations using CSS3 and JavaScript.
Understanding of rendering engines, pixel densities, and how to build fast and reliable applications.
Comfort with custom UI (not relying on standard OS controls).
A strong grasp of motion design, easing functions, and the math/physics behind them.
A builder’s mindset — you love pushing the limits of what’s possible.
A healthy respect for work-life balance — including your own circadian health.
Compensation package:
We offer a competitive compensation package, including a market-leading salary and stock options.
