Cosign · 15 hours ago
Senior Full-Stack Engineer — Ruby on Rails (Proptech or Fintech Experience Preferred)
United States
Full-time
Remote
Senior Level
5+ years expCosign is the fastest growing proptech company in the United States revolutionizing the rental industry with a market-leading rent guarantee product. As a Senior Full-Stack Engineer, you will be a core technical contributor building and scaling the product, working closely with various teams to deliver features that enhance housing access and landlord occupancy.
Financial Services
Responsibilities
Build high-impact full-stack features that directly help renters secure housing and landlords increase occupancy
Design, implement, and scale backend systems as Cosign grows rapidly
Collaborate with Product and Leadership on roadmap planning, technical architecture, and system design decisions
Own features end-to-end—from backend logic and APIs to frontend implementation
Improve reliability, performance, and developer experience across the codebase
Contribute to technical standards, best practices, and long-term platform scalability
Qualification
Required
5+ years of professional engineering experience with strong Ruby on Rails expertise
Strong React / JavaScript experience (frontend is React-focused)
Full-stack mindset—you're comfortable working across backend, frontend, and infrastructure
CS degree or equivalent engineering background
Ability to thrive in a fast-paced startup environment with high ownership and minimal process
Strong problem-solving skills and comfort working in ambiguous problem spaces
Preferred
Proptech or Fintech Experience Preferred
Benefits
Top-of-market health benefits
Laptop and full equipment setup provided
Team offsites twice per year
Company
Cosign
11-50 employees
Funding
Current Stage
Early StageCompany data provided by crunchbase