Senior Full-Stack Engineer

Sellsig; Minnesota; On-site; USD 90,000 - 120,000; Full time

Job summary

Sellsig is looking for a full-stack developer in Minnesota to design and implement features across our React and Supabase platforms. You’ll engage in all stages of feature development, prioritizing code quality and performance.

The ideal candidate will have over 5 years of experience with web applications, solid TypeScript knowledge, and familiarity with real-time systems. Join us to impact product decisions directly through real sales interactions.

Qualifications

• 5+ years of experience in web application development.
• Strong knowledge of TypeScript and modern React frameworks.
• Experience with SQL and Postgres database systems.

Responsibilities

• Design, build, and ship full-stack features using React/TypeScript and Supabase.
• Own features end to end from scope to deployment.
• Profile and fix latency and rendering regressions on the live coaching UI.

Skills

5+ years building and shipping production web applications

Strong TypeScript and modern React

Solid relational data modeling and SQL

Experience with Supabase and edge functions

Real-time systems experience

Job description

Own features end to end across our React + TypeScript front end and Supabase/Postgres back end — from the live coaching UI reps stare at on every call to the edge functions that serve cue cards in under a second. You ship weekly, sit on real sales calls, and care as much about the product as the code.

What you'll do

• Design, build, and ship full-stack features across React/TypeScript, Tailwind, and Supabase (Postgres, edge functions, RLS).
• Own problems end to end: scope, build, test, deploy, and measure — not just close tickets.
• Keep the live coaching surface fast and reliable; profile and fix latency and rendering regressions.
• Write clear, reviewable code and thoughtful PRs; raise the bar on testing and observability.
• Pair with product and design, and sit on real sales calls to ground decisions in how the product is actually used.

What we're looking for

• 5+ years building and shipping production web applications.
• Strong TypeScript and modern React (hooks, data fetching, performance).
• Solid relational data modeling and SQL; comfort with Postgres.
• Experience owning features from design through deploy in a fast release cadence.
• Clear written communication and an async-first working style.
• Supabase, edge/serverless functions, or row-level-security experience.
• Real-time systems (WebSocket/WebRTC, streaming) or low-latency UI work.
• Early-stage startup experience.

How we hire

Our process has a few stages — it's a real role, so we take it seriously on both sides:

• Intro call with the hiring manager — the role, your background, and what you want next.
• Team conversations — meet the people you'd work with day to day.
• A practical exercise drawn from real work — no whiteboard puzzles, no weekend-eating take-homes.
• An on-site visit to our Saint Paul office to meet the team in person.
• Final conversation and references, then an offer.

We move as quickly as we can and keep you posted at every step.

Not a perfect match?

If you'd be great at this work, tell us how you'd approach it. We read every note.