AI Platform Engineer

Light; Greater London; On-site; GBP 80,000 - 100,000; Full time

Job summary

A modern tech company in Greater London is seeking a Senior AI Platform Engineer to architect the internal AI Engine. Responsibilities include designing a robust Agent Runtime, implementing reliability frameworks, and evolving internal tools for product engineers. The ideal candidate will have a strong systems engineering background and a passion for AI. Competitive salary and stock options are part of the offer, along with 25 days of annual leave and an opportunity to greatly impact the product and culture.

Benefits

Competitive salary + potential stock options

25 days of annual leave + public holidays

Regular socials and company off-sites

Qualifications

• Significant experience building scalable backend systems.
• Proficient understanding of AI and the latest technologies.
• Strong knowledge of clean API design.

Responsibilities

• Design and build a production-grade Agent Runtime.
• Evolve internal GenAI Client and SDKs.
• Implement reliability frameworks for AI.

Skills

Systems Engineering

AI Knowledge

Kotlin

Clean APIs

Problem-solving

Job description

About Light.

Light exists to replace factory-era ERPs with software that feels alive. Our Smart Financial Platform gives modern, global companies superpowers—automated accounting, real-time reporting, and financial flows that move at the speed of the business.

We build with our customers, ship fast, and obsess over craft. In a short time, Light has gone from idea to the operating core for leading companies like Lovable, Legora, and Keyshot. People don’t just use Light—they enjoy it.

We’re an early team defining a new software category. Think engineers who love debits and credits, designers who care about reconciliation states, and operators who treat finance as a product. If you’re excited to modernize how the world runs money—one workflow at a time—you’re in the right place.

Backed by world-class investors and advised by industry titans, we’re building category-defining products with the freedom to ship ambitiously and own outcomes. Come help us make Light the global default for next-gen finance.

The AI Platform Engineer Role

You will join the Foundation Team, the force multiplier for our entire engineering organization. Our mandate is to "build the factory that builds the product." As a Senior AI Platform Engineer, you will not just be tuning prompts, you will be architecting the internal "AI Engine" that powers every AI feature at Light.

We are looking for a systems thinker who is obsessed with the bleeding edge of AI but grounded in the reality of production engineering. You will help us move beyond simple API wrappers to build a robust Agent Runtime, define our internal standards for AI reliability, and ensure our product teams can ship deterministic, high-quality AI features in days rather than weeks.

What you will do

• Architect the Engine: Design and build a production-grade Agent Runtime that handles tool registration, permissions, timeouts, and retry semantics for autonomous agents.
• Define the Standard: Evolve our internal GenAI Client and SDKs to create a "paved road" for product engineers, standardizing how every team at Light interacts with LLMs.
• Solve for Trust: Build the "CI/CD for AI", implementing reliability frameworks, golden datasets, and regression testing pipelines that allow us to deploy prompts and agents with confidence.
• Expand the Ecosystem: Lead the integration of Light with external platforms via the Model Context Protocol (MCP) and automation tools like n8n.
• Governance & Scale: Design the guardrails, rate limits, and caching strategies that ensure our AI infrastructure scales predictably and cost-effectively.

What you will need

• Strong Systems Engineering Background: You have significant experience building scalable backend systems or internal developer platforms. You care deeply about latency, observability, and clean APIs.
• AI Native Mindset: You live on the bleeding edge of the AI landscape. You understand the difference between an Agent and a Chain, you have experimented with MCP, and you keep up with the latest releases from OpenAI, Anthropic, and DeepSeek.
• Polyglot Capabilities: You are proficient in Kotlin (our core backend language) or have a strong willingness to learn it.
• Focus on Determinism: You hate flaky software. You understand that trust is the biggest bottleneck to AI adoption, and you know how to build the evaluations and logging necessary to generate that trust.
• Force Multiplier Attitude: You get more satisfaction from unblocking 10 other engineers with a great tool than from shipping a single feature yourself.

The good stuff

• 💸 Competitive salary + potential stock options
• 🏝 25 days of annual leave + public holidays (in your country)
• 🥳 Regular socials and company off‑sites.
• 🚀 A huge opportunity to shape a market‑defining product and engineering culture

The famous last words

At Light, we’re building the most trusted financial platform in the world — and trust starts with security. As our Security Lead, you’ll help us earn that trust every day.

Join the rocket ship while it’s taking off 🚀