Full Stack Engineer

About the Company

Arc One is hiring a senior full stack developer to own an internal product. First dedicated engineer. Reports to the founder. Small team, fast pace.

About the Role

A senior full stack developer to own an internal product.

Responsibilities

• Own a Next.js 16 App Router codebase end to end.
• TypeScript across the stack.
• Maintain Postgres schema via Drizzle migrations.
• Own auth, RBAC, and security.
• Better Auth org and admin plugins, 2FA, per route ownership checks.
• Iterate on similarity search built on pgvector.
• Maintain the LLM judge evaluation harness.
• Integrate OpenAI and Anthropic SDKs.
• Manage prompt caching, model selection, and cost.
• Review every PR before merge, including those from AI assisted coding workflows.
• Own Vercel deployment and Vitest coverage on mutation routes.

Qualifications

• 3+ years professional experience.
• At least one production B2B SaaS owned as technical lead, not as a contributor.

Required Skills

• Deep TypeScript knowledge.
• Production Next.js App Router. Server components, server actions, streaming. Pages Router only does not count.
• Postgres at the schema and query optimization level. You have shipped non trivial migrations.
• Drizzle, Better Auth, shadcn, pgvector, OpenAI or Anthropic SDKs in production.
• You can articulate the difference between IDOR, broken access control, and a missing 404, and you know which one is worse.
• Direct written communication. PR reviews that say no with reasons and yes with specifics.

How to apply

Please email your CV along with

• Two production codebases you have shipped, one line each on your role.
• One paragraph about a system you owned end to end and would do differently today.