Senior Software Engineer (Full Stack)

Sonar•New York City, NY

14d•Onsite

About The Position

About Sonar Sonar’s an early-stage start up revolutionizing the limited partner (LP) tech stack. Allocators like sovereign wealth funds, university endowments, insurance companies, and family offices invest in a variety of assets — either directly or through managed funds. Yet, the systems available today are woefully inadequate for their needs. We’re changing that. We hope you'll join this mission! We work in the office every day, not because we have to, but because we want to. The work is genuinely meaningful, and while we take work very seriously, we don’t take ourselves too seriously. We founded Sonar because we wanted to build two things: A generational company that outlasts us A culture that we wish we had at the companies we worked for And as much as we care about your technical prowess, we’re looking for a good culture fit. Bonus points if you have good taste in music! The Role Engineering at Sonar sits at the intersection of AI, finance, and infrastructure. You’ll be designing systems that power AI-driven fund diligence and portfolio management for institutional investors. You’ll work across the stack, from distributed systems and scalable data ingestion pipelines to AI agents and reporting interfaces that LPs rely on daily. This role is ideal for someone who’s looking to jump into an early-stage environment (i.e. you’ll be figuring out a ton of things with us), enjoys thinking from first principles, and wants to build durable systems that reimagine how capital allocators evaluate and invest.

Requirements

Bachelor’s or Master’s degree in Computer Science, Engineering, or a related field, with strong fundamentals in algorithms, systems design, and data structures.
5+ years of professional software engineering experience, ideally including time at a high-growth startup or technology company.
Deep experience building and scaling full-stack systems—from cloud infrastructure and backend APIs to modern frontend applications.
Proficiency with TypeScript, React, and Node.js.
Solid understanding of distributed systems, data modeling, and performance optimization.
Experience designing and maintaining systems on AWS (or equivalent cloud platforms), including CI/CD, observability, and infrastructure-as-code.
Working knowledge of PostgreSQL, Redis, and modern workflow or job orchestration tools (e.g., Temporal, Inngest, Airflow).
Comfort building with and around AI tools—integrating LLMs, retrieval pipelines, or structured evaluation workflows.
Strong communication and collaboration skills; ability to operate autonomously in an early-stage environment and drive projects from idea to production.
Excitement for joining a small, ambitious team and helping shape both the product and the engineering culture from day one.

Responsibilities

Build core systems from the ground up.
Design and implement the foundations of Sonar’s product—from scalable APIs and distributed data pipelines to intuitive interfaces that bring complex information to life.
Work across the stack. You’ll move between backend services, frontend components, and infrastructure, shipping features end-to-end.
Apply AI pragmatically. Develop, evaluate, and productionize LLM-based features that make complex analysis simpler and faster for real users.
Make it fast, reliable, and observable. Build systems that perform under load, recover gracefully, and are easy to monitor and improve.
Set the standard. As an early engineer, you’ll shape engineering practices, influence architecture, and help define the culture of a company that values thoughtful work.