Senior UI Engineer Jobs in San Francisco, CA

ABOUT THE ROLE

Together AI is seeking a highly experienced Staff Engineer to join the Product Engineering team, to own and evolve the Product UI Platform — the architectural foundation that powers how product teams build full-stack features across our web surface. This role is responsible for evolving the product runtime from its current monolithic growth architecture to a scalable, modular, and high-leverage platform that supports increasing scale, reliability requirements, and a growing number of feature engineers. You will define and drive the technical direction of the Next.js/typescript/nodejs web runtime, BFF layer, and application integration patterns, partnering peer-to-peer with Backend and API Platform leaders to ensure cohesive architectural evolution across layers. This is a deeply hands-on role for an experienced engineer with real life experience leading and implementing architectural evolution and is ready to take full ownership of a critical technical domain.

Responsibilities

- Lead the next phase of architectural evolution for the product application platform
- Design and implement foundational platform primitives used across product teams
- Reduce architectural entropy and duplication across the web surface
- Improve application-level performance and reliability metrics
- Drive incremental modularization without disrupting feature velocity
- Establish performance budgets and enforce application-layer guardrails
- Partner with Backend Platform to shape API ergonomics and integration boundaries
- Collaborate with SRE to ensure runtime stability and production readiness
- Write and maintain critical-path platform code
- Establish durable standards for how full-stack features are built
- Mentor engineers and help scale the platform capability over time

REQUIREMENTS

- 8+ years building production-grade web applications and backend systems
- Demonstrated ownership of a product application platform used by multiple teams
- Deep expertise in React/Next.js/TypeScript and server-side application architecture
- Strong backend experience with TypeScript
- Experience evolving monolith architectures into modular systems
- Web Vitals performance optimization experience across browser → API → data layers
- Proven ability to drive and implement architectural change in a cross functional collaborative environment
- Experience establishing technical standards and scaling developer velocity
- History of owning complex technical decisions and their outcomes

ABOUT TOGETHER AI

Together AI is a research-driven artificial intelligence company. We believe open and transparent AI systems will drive innovation and create the best outcomes for society, and together we are on a mission to significantly lower the cost of modern AI systems by co-designing software, hardware, algorithms, and models. We have contributed to leading open-source research, models, and datasets to advance the frontier of AI, and our team has been behind technological advancement such as FlashAttention, Hyena, FlexGen, and RedPajama. We invite you to join a passionate group of researchers in our journey in building the next generation AI infrastructure.

COMPENSATION

We offer competitive compensation, startup equity, health insurance and other competitive benefits. The US base salary range for this full-time position is: $200,000 - $275,000 + equity + benefits. Our salary ranges are determined by location, level and role. Individual compensation will be determined by experience, skills, and job-related knowledge.

EQUAL OPPORTUNITY

Together AI is an Equal Opportunity Employer and is proud to offer equal employment opportunity to everyone regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability, gender identity, veteran status, and more. Please see our privacy policy at https://www.together.ai/privacy