Senior Software Engineer Funded Fintech (Index Ventures Lead)

About the Company - Day One is partnering with a fast-growing fintech company to hire 5 Senior Software Engineers over the next two months. This client is transforming financial operations in a massive, traditional industry by using AI and automation. This is a full-time, on-site role in San Francisco.

About the Role - As a Senior Software Engineer, you’ll:

Build and maintain key features in a high-scale fintech platform

Work across the stack using Ruby on Rails and Next.js

Develop intuitive dashboards and checkout flows

Own projects from design to deployment

Collaborate with cross-functional teams (product, design, customers)

Improve system reliability and scalability

Mentor other engineers and help shape engineering practices

Responsibilities - Engineers will work on complex backend systems and customer-facing applications that handle high-volume financial transactions.

Qualifications - 5+ years of backend or full stack engineering experience

Required Skills - Proficiency with relational databases, Experience scaling web-based products, A desire to work on complex systems with real-world impact

Preferred Skills - Bonus: Experience with Ruby on Rails, Next.js, API development, or fintech/payment products