AI Engineer – London

About Sequence

If you join Sequence, you’ll help build the platform that lets companies get paid—we’re already processing more than £1bn in annual invoice volume and growing fast. We are building an AI‑powered revenue platform for modern finance teams, replacing fragile spreadsheets and legacy systems with software their teams love.

What you’ll be doing

We care deeply about the quality of the product we’re building. We’re looking for engineers who are ambitious and take ownership end‑to‑end: from identifying what to build, through shipping, to making sure it works for real customers. Here’s what you might work on:

• Our AI infrastructure: build and own the platform that allows us to build reliable software on top of non‑deterministic models, including agentic workflows, prompt iteration, tools, and evals.
• AI‑powered approval workflows: build flexible routing that customers configure in natural language—e.g., “require VP approval for deals over £100k with annual terms”—and turn that into deterministic, auditable business logic.
• An intelligent collections agent: build an agent you instruct in natural language—e.g., “send a reminder at 7 days overdue;escalate at 14 days” – which then runs the entire workflow and collects relevant context autonomously.

You should apply if

• You’ve shipped LLM‑based systems to real customers and have first‑hand experience with how they fail in production.
• You’ve designed agentic systems and have informed views on the building blocks (embeddings, memory, tool use, long‑running state, recovery from partial failures) and when to reach for each.
• You’ve built evals infrastructure (datasets, LLM as judge, prompt regression tests, monitoring) and have a clear view of what good looks like.
• You respect the weight of building business‑critical systems on top of non‑deterministic models and are comfortable writing resilient software.
• You have informed opinions about the tooling for building, evaluating, and securely running multi‑provider AI systems in production.
• You’ve shipped production backend systems and care about the difference between “it works” and “it’s reliable”.
• You care about customers— you want to understand why you’re building something, not just what.
• You’re comfortable with ambiguity, thrive in early ideation stages, share work‑in‑progress to gather feedback, and adapt easily based on input.
• You communicate clearly; thoughtful communication is a superpower that sharpens how we collaborate and build.

Tech stack

• Backend: Kotlin (modular monolith using Http4k, Spring Boot, Exposed, Result4k)
• Storage: Postgres, BigQuery
• AI Platform: VertexAI, Langsmith, and more
• Async messaging: Google Cloud Pub/Sub
• Infrastructure: Google Cloud, Terraform
• Frontend: TypeScript, React
• Monitoring: GoogleCloudMonitoring, Sentry
• Tools: GitHub, Slack, Notion, Linear

What we offer

• Salary: £115,000–£130,000
• Equity: Meaningful share options
• 25 days holiday+bank holidays

#J-18808-Ljbffr…