Help us build an AI-native platform where segmentation, analysis and activation happen through conversation, not configuration. Lexer is a Customer Data Platform that’s been helping retail and hospitality brands understand and act on their customer data for seventeen years. We’re now rebuilding what a CDP can be: an AI-native platform where the hard work of segmentation, analysis, and activation happens through conversation, not configuration. We’re looking for a Principal Engineer to work with our AI product teams on the hardest technical problems we have. About the roleThis is the most senior individual-contributor engineering role at Lexer. You’ll shape how the engineering organisation builds, through demonstrated technical authority and the quality of the systems you create. At its core this is a software engineering role. You're building and operating a SaaS and data platform product that our customers rely on every day — multi-tenant, always-on, and held to a high bar for quality, performance and reliability. We’ve transitioned to agentic harness engineering and spec-driven development, where engineers direct AI agents and maintain the systems that produce software rather than writing all of it by hand. Role details- Level: Principal Engineer — the most senior individual-contributor role in engineering.- Reports to: CTO.- Experience: 8+ years of hands-on software engineering, including significant time operating at a senior/staff level across complex systems.- Location: Remote or Hybrid — Melbourne-based (3 days/week in our St Kilda office; 2 days WFH). Remote considered with strong overlap with AEST/AEDT core hours. How we workWe practice spec-driven development inside an agentic harness: engineers direct AI agents and maintain the systems that produce software. Our engineering culture draws on XP — test-first, continuous integration, small batches, pairing, and shared ownership. Our stackPredominantly Python and React on AWS, with data processing in Databricks.