Fullstack Engineer

• Build and ship end-to-end features across the customer web app, API layer, browser extension, and third-party integrations
• Design APIs and data flows across Postgres/Supabase, OpenSearch, DynamoDB, and S3
• Build durable background job synchronisation, bulk enrichment, scheduled jobs, and webhooks
• Keep the codebase typed, tested, and observable
• Own code review and shipping discipline
• Build autonomous tools and copilots using frameworks such as Mastra and CopilotKit
• Integrate Claude, OpenAI, and other LLM APIs, including tool calling, RAG, agents, structured output, and evaluations
• Extend CRM integrations across HubSpot, Salesforce, Nango, and Paragon
• Write technical specifications explaining trade-offs and scope
• Communicate technical decisions clearly and raise risks early
• Work alongside product, design, and the Australian engineering team
• Own features from specification through production in Firmable’s AI-powered B2B sales intelligence platform

• 5+ years shipping production web applications and Next.js products at scale
• Strong backend fundamentals, including REST API design, relational data modelling in Postgres, authentication and multi-tenancy patterns, and background job architecture
• Hands-on experience shipping agentic AI features using LLMs, including tool calling, RAG, agents, structured output, and evaluations
• Daily use of Claude Code, Cursor, or similar AI-native development tools for API design, debugging, code review, test coverage, and architectural thinking
• Very good written and verbal English communication
• Ability to communicate technical decisions to engineers and non-technical stakeholders
• Ownership mindset and ability to take ambiguous problems through to measurable outcomes
• Experience with Turborepo or equivalent, Tailwind, Radix/Shadcn design systems, TanStack Query, and Zustand is highly valued
• Experience with Clerk organisations and RBAC and Stripe usage-based billing is highly valued
• AWS infrastructure experience, including Lambda, OpenSearch, and DynamoDB, is highly valued
• Browser extension experience with Plasmo or similar frameworks and Chrome extension patterns is highly valued
• Experience building MCP servers or agent evaluation and observability frameworks is highly valued
• Startup or scaleup experience is highly valued

• Flexible remote work arrangement in India
• Flexible working environment
• Career progression opportunities into technical leadership, architecture, or AI systems specialisation