Senior Software Engineer (NYC)

Onshore builds AI-native tax software for the people who build America. Farmers, manufacturers, and founders do the R&D that moves this country forward — and most never get the credit they've earned. We're fixing that: our agents do the analysis that used to take CPAs weeks, our experts review it, and our customers get their money back. We started with R&D tax credits and are expanding into agricultural incentives, corporate tax returns, and other tax incentives.

We're hiring a Senior Software Engineer to lead technical work across the platform and raise the bar for everyone around them.

What you'll do

• Architect and ship complex systems across our stack: TypeScript end-to-end, Bun + Hono on SST v3 (Lambda, ECS/Fargate, SQS), Aurora Postgres with Drizzle, Vite + React on the front.
• Lead one of our four platform builds: the core R&D credit engine, agriculture incentives, corporate tax and compliance (versioned calc graph, MeF e-file), or agentic infrastructure (verification layers, evals, RAG over primary tax authority).
• Design agent workflows where wrong answers have real consequences — verification, calibration, and audit-defensibility are the product.
• Mentor engineers at every level, lead design reviews, and shape engineering practice as we scale from ~10 toward 20.
• Partner directly with founders, tax experts, and customers to turn ambiguous problems into shipped product.

Our stack

• TypeScript end-to-end — Bun + Hono services, Vite + React (shadcn, Tailwind) on the front.
• SST v3 on AWS: Lambda, ECS/Fargate, SQS, Step Functions.
• Aurora Postgres with Drizzle ORM, Pinecone for RAG, Clerk for auth.
• Frontier LLMs powering extraction, analysis, and agent workflows.

You should have

• 5+ years building production software, with deep full-stack experience.
• Strong systems judgment — you've owned architecture decisions and lived with their consequences.
• Experience shipping LLM-powered products, data pipelines, or high-stakes automation is a strong plus.

Compensation

• $225k base
• equity
• Full benefits