Hairball

Hundreds of companies of all sizes partner with Hairball to automate, integrate, and transform their business.

Senior Full-Stack Engineer

Full-stack EngineerSoftware EngineerContractRemoteSeniorTeam 11-50Since 2021Company Site LinkedIn

Location

United States

Posted

7 days ago

Salary

Not specified

Seniority

Senior

Bachelor Degree0.5 yrs expEnglishJavaScriptNext.jsPostgreSQLTypeScript

Job Description

• We need a senior full-stack engineer to build the multi-tenant platform foundation for a new SaaS product over a 6-month contract engagement. • You will be the primary architect and builder of the core infrastructure. • A junior JavaScript developer on the team will work alongside you, learning the stack and eventually owning day-to-day development after your engagement ends. • The architecture decisions you make in the first 8 weeks will shape this product for years. • Months 1-2: Platform Spine. • Months 3-4: Billing & Integrations. • Months 5-6: Hardening & Handoff.

Job Requirements

Multi-tenant SaaS architecture: You have personally built (not just contributed to) a multi-tenant application with tenant data isolation.
PostgreSQL Row-Level Security: You have implemented RLS policies in production.
Next.js 14+ App Router: You are current with App Router (not Pages Router).
TypeScript: You write TypeScript fluently, not JavaScript with type annotations bolted on.
Stripe Billing integration: You have wired up subscriptions, handled webhooks with signature verification, and implemented metered/usage-based billing.
Multi-org authentication: You have implemented multi-organization auth (Clerk, Auth0, or similar) in a SaaS product.
Strongly Preferred Experience with Drizzle ORM (or Prisma with willingness to learn Drizzle).
AI/LLM application development — calling LLM APIs, streaming responses, token tracking.
Vercel deployment and optimization.
Experience mentoring junior developers.
Prior work in e-commerce, fintech, or financial data platforms.

Benefits

Complete architecture spec: A detailed specification covering every subsystem you will build. You are implementing a well-defined plan, not designing from scratch.
Deep domain expertise: The product owner has deep expertise in the target market. You will never be guessing about business requirements.
Working prototype: The backend pipeline and database schema already exist. You are building on a foundation, not from zero.
AI development tooling: Claude Code is available as a pair programmer.
Autonomy: You make the technical decisions within architectural boundaries. No micromanagement.
Weekly video check-in, daily async on Slack.