Senior Full Stack Engineer

Role Overview

The Senior Full Stack Engineer (AI) at Firmable is responsible for shipping end-to-end features from database to frontend. You will own work from specification through production, collaborating with product and design teams based in Melbourne.

Daily Responsibilities:

• Feature Shipping: Build and ship across the customer web app (Next.js), API layer (TypeScript), browser extension, and third-party integrations. Design APIs using Postgres, OpenSearch, DynamoDB, and S3.
• Data Architecture: Construct durable background jobs, bulk enrichment tasks, scheduled syncs, and webhooks for real-time data flows.
• AI Integration (Core Focus): Build agentic systems using frameworks like Mastra and CopilotKit. Implement RAG pipelines, structured outputs, tool calling with LLM APIs (Claude, OpenAI), and agent evaluations.

Technical Requirements:

• Experience: 5+ years shipping production web apps at scale using Next.js.
• Backend Fundamentals: Strong grasp of REST API design, relational modeling (Postgres), auth/multi-tenancy patterns, and background job architecture.
• AI Proficiency: Hands-on experience with LLM workflows; comfort debugging agent failures. Must use AI tools like Claude Code or Cursor as your primary coding partner daily.

Nice-to-Haves:

• Turborepo monorepos, Tailwind/Shadcn design systems.
• Clerk for authentication (RBAC) and Stripe usage-based billing experience.
• AWS infrastructure knowledge (Lambda, DynamoDB).
• Browser extension development (Plasmo framework).