Senior Full Stack Engineer (AI)

Firmable Pty Ltd; City of Melbourne; Hybrid; AUD 120,000 - 180,000; Full time

Job summary

Firmable Pty Ltd is seeking a senior software engineer to build AI-powered production web apps using Next.js and robust backend fundamentals. You will design REST APIs, model data in Postgres, and implement multi-tenancy with scalable background jobs.

You will ship features using LLMs, tool calling, RAG, and agents, with structured output and strong debugging discipline. Claude Code or Cursor will be part of your daily workflow for planning, review, and validation of AI output.

Qualifications

• 4+ years shipping production web apps with Next.js.
• Strong backend fundamentals: REST APIs, PostgreSQL modelling, auth and multi-tenancy.
• Hands-on with agentic AI: shipped features using LLMs, tool calls, RAG, agents, structured output.
• AI-native workflow: daily use of Claude Code or Cursor for planning, delegation and review.
• Excellent written English for async updates, specs and PRs; proactive risk communication.
• Ownership mindset: delivering ambiguous problems to measurable outcomes.
• Daily use of AI tools for API design, debugging, code review, test coverage and architecture.

Skills

Next.js

Production Web Apps

REST APIs

PostgreSQL

Auth & Multi-tenancy

Background Jobs

LLMs & AI

Tool Calling

RAG

Agents

Structured Output

Debugging

Code Review

Test Coverage

Architectural Thinking

English Communication

Ownership Mindset

Tools

Claude Code

Cursor

Job description

Requirements:

• 4+ years shipping production web and Next.js : you've built real products end-to-end and shipped them at scale.
• Strong backend fundamentals: REST API design, relational data modelling in Postgres, auth and multi-tenancy patterns, background job architecture.
• Agentic AI hands-on: you've shipped features using LLMs (tool calling, RAG, agents, structured output, evals); you can explain what broke and how you debugged it.
• AI-native workflow: you use Claude Code, Cursor or similar as your default way of working, every day. You plan, delegate, review and verify AI output thoughtfully.
• Very good communication: clear written English in async updates, technical specs, and PR descriptions; confidence in conversations with stakeholders; you raise risks early.
• Ownership mindset: you take ambiguous problems through to shipped, measurable outcomes.
• You live and breathe AI tools. You use AI daily for API design, debugging, code review, test coverage, and architectural thinking as your default way of working, not a productivity experiment. In 2026, this is how strong engineers move fast, and you need to already be doing it.