Software Engineer

Mosaic • New York City, NY

5d

About The Position

As a Fullstack Engineer at Mosaic, you’ll build product experiences that investors and bankers rely on to run high-stakes deal processes. You’ll work across the stack—from sleek, high-trust interfaces to backend services that power modeling, ingestion, collaboration, and workflow automation. This is a role for builders who want real ownership. You’ll ship features end-to-end, collaborate tightly with product and design, and help establish the technical foundations for a platform used in mission-critical environments. You’ll tackle challenging problems like structured financial computation, document ingestion, auditability, permissions, real-time collaboration, and performance at scale. Your work will directly impact how the world’s most sophisticated financial teams evaluate acquisitions, credit investments, and major corporate decisions.

Requirements

• 2–6+ years of experience building modern web applications
• Comfortable working across frontend + backend and owning features end-to-end
• Strong Frontend Fundamentals
• Experience building clean UIs with modern frameworks (React preferred)
• Strong instincts around usability, quality, and UI performance
• Backend & Systems Capability
• Experience building APIs and services (Node, Python, Go, etc.)
• Strong data modeling instincts and comfort working with relational databases
• Familiarity with cloud infrastructure and production systems
• High Ownership / Startup Mentality
• Self-starter who thrives in fast-moving, unstructured environments
• Bias toward action, shipping, and iterating quickly with the team
• Thoughtful Collaborator
• Clear communicator who enjoys working cross-functionally
• Excited to pair, review code, and build internal momentum

Nice To Haves

• Experience building tools for finance, analytics, or high-compliance workflows
• Familiarity with AI product patterns (LLMs, agents, structured extraction)
• Experience with workflows involving spreadsheet-like interactions
• Exposure to observability tooling, performance profiling, or infra work

Responsibilities

• Build End-to-End Product Experiences
• Own features from idea → design → implementation → testing → deployment
• Build intuitive, polished UI workflows that feel fast and trustworthy
• Ship backend APIs and services that support complex user actions and data flows
• Design Systems that Scale
• Improve the architecture of core systems powering modeling and analysis
• Write clean, maintainable, well-tested code that raises the team’s bar
• Ensure performance and reliability for workflows used in live deal environments
• Work in a High-Trust, High-Accuracy Domain
• Build with auditability and correctness in mind
• Help define patterns for permissions, versioning, and reproducibility
• Balance velocity with quality in a product where accuracy matters
• Collaborate Deeply with Product & Customers
• Partner with product, design, and GTM teams to translate needs into product
• Incorporate feedback from real customer workflows (often built in Excel)
• Contribute to roadmap shaping through technical insight and execution
• Drive Engineering Excellence
• Participate in code reviews, technical design discussions, and system planning
• Improve developer tooling, observability, and internal infrastructure
• Help define best practices as the engineering org scales

Benefits

• A competitive base salary
• An early-stage start-up equity package designed to create life-changing wealth when we win as a team.
• Health, vision & dental coverage
• Unlimited PTO
• Unforgettable team building events, offsites, and happy hours

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed