Software Engineer

We're partnering with a well-established UK marketing services business on a key first hire as they build out an in-house engineering function for the first time.The company works with a portfolio of high-growth consumer brands and is investing seriously in becoming AI-native. They're building a proprietary internal platform that will sit at the centre of how the team delivers work and how clients experience it: think workflow tooling, automation, alerting and AI-driven analysis layered on top of a rich, proprietary dataset.This is a genuine ground-floor role. You'll be the first engineer dedicated to the build, working closely with the senior leadership team. Real ownership, no legacy codebase, and you set the technical bar for everyone who follows.What you'll doShip production features into a platform the team and its clients rely on daily.Build on a modern serverless stack (Supabase, Vercel, the Vercel AI/Agent SDK), using Claude Code or Codex as a core part of how you architect and ship, not as autocomplete.Own the data layer, designing the structures that make a complex, messy domain queryable by both people and agents.Design for scale early. Schemas, auth boundaries and agent orchestration built to hold up as usage grows across the business and its client base.Set the engineering standards (testing, evals, deploy hygiene, observability) that future hires inherit.Judge when a deterministic pipeline beats an agentic loop, and design against LLM failure modes (prompt injection, hallucinated tool calls, data exfiltration) by default.What our client is looking for2+ years of professional software engineering, with AI genuinely central to how you work.Real fluency with Claude Code, Codex or an equivalent agentic tool. You can talk through how you architect work for them and where they fall over.Solid modern web fundamentals: TypeScript, React/Next.js, backend APIs, Postgres. Experience with a Supabase/Vercel-type stack is a plus.A track record of turning messy domains into clean, queryable data structures.Familiarity with agent architecture (planners, tool use, memory, evals, guardrails) is a strong plus.You've shipped software real users depend on and can talk through the trade-offs.The right person thinks in systems, moves fast, and operates more like an architect than a builder. High ownership, low ego, comfortable making calls under uncertainty.The detailsLocation: London, hybrid (a couple of days a week in office).Salary: £62,000, plus a solid benefits package (private healthcare, pension, generous holiday, professional development budget and a work-abroad scheme).Client name shared with shortlisted candidates. If you want to build something a business is genuinely betting on, rather than maintain someone else's, get in touch for a confidential conversation.