Senior Product Engineer

Sarah Smith Fund; Greater London; Hybrid; GBP 110,000 - 150,000; Full time

Benefits offered by this job

Salary

Equity

Holidays

Office in London

Dinner allowance

Work-from-anywhere

Pension plan

Team events

Founders collaboration

Job summary

Kernel is looking for a high-velocity product engineer to join its London team. You will design and ship features that power large-scale AI-driven workflows, owning projects end-to-end—from ideation to deployment—in a small, autonomous setting.

The role requires 6+ years in software or product engineering, strong backend chops with NodeJS, PostgreSQL and TypeScript, and experience with LLM patterns (RAG, prompt engineering). London office, visa sponsorship, equity, and a fast-paced culture await.

Qualifications

• 6+ years of software or product engineering experience.
• Experience building and scaling production systems.
• Comfort with backend engineering (NodeJS, Postgres, TypeScript).
• Familiarity with LLM application development patterns (RAG, prompt engineering).
• Ability to operate autonomously in a small, high-velocity team.
• Excellent communication and collaboration skills.
• Some experience with Kubernetes or distributed systems.

Responsibilities

• Designing and developing product features that directly impact user workflows.
• Collaborating with design, product, and other engineers to deliver exceptional user experiences.
• Writing and maintaining clean, reliable, and scalable code across the stack.
• Helping ensure performance and reliability for large-scale data operations.
• Automating workflows to improve developer velocity and reduce manual work.
• Supporting integrations with CRMs and third-party APIs.
• Participating in roadmap discussions and contributing technical insights.

Skills

NodeJS

PostgreSQL

TypeScript

LLM patterns

RAG

Kubernetes

Autonomy

Communication

Tools

AWS

Next.js

n8n

Tailwind

Job description

About Kernel

Agents are starting to sell, buy and operate on behalf of companies. But before an agent can close a deal, qualify an account, route a lead or assess risk, it has to answer a basic question: which company is this?

Today, that answer is messy, and no one answers it reliably. Business identity lives across CRMs, ERPs and third-party datasets full of duplicates, missing parent companies, stale addresses and incorrect enrichment. The cost shows up across the enterprise: sales teams miss revenue opportunities because they lack the right account context; operations teams take on avoidable exposure because risk signals are fragmented or wrong; and finance teams end up chasing, writing off, or defaulting on bad debt that should have been caught earlier.

Humans have worked around that mess for years. Agents cannot. They need a reliable business identity layer they can trust.

Kernel is building that layer: the business registry for agents. We issue a permanent KERN ID for every business, plus the context an agent needs to act on it. Ops, data and revenue teams at Gong, Legora, Mistral, Canva and Checkout already use Kernel on their own systems. Agents are next, and there will be far more of them.

We have raised $20M from top VCs and operators at Plaid, OpenAI, Slack and others, and we are growing 5x YoY.

The Role

You are a T-shaped product engineer with a spike in backend engineering. You will work closely with the product and engineering team to build user-facing features, ship at pace, and support the existing infrastructure as we scale. You do not need to be a DevOps expert, but familiarity with AWS and Kubernetes is valuable.

You take initiative, adapt quickly, and communicate clearly. The team is small and fast-moving, so you’ll be expected to make decisions and ship code autonomously. You will help the company grow from $3M to $30M ARR, owning projects end-to-end—from ideation to deployment—while helping shape how we build products and infrastructure at Kernel.

What You’ll Be Doing

• Designing and developing product features that directly impact user workflows

• Collaborating with design, product, and other engineers to deliver exceptional user experiences

• Writing and maintaining clean, reliable, and scalable code across the stack

• Helping ensure performance and reliability for large-scale data operations

• Automating workflows to improve developer velocity and reduce manual work

• Supporting integrations with CRMs and third-party APIs

• Participating in roadmap discussions and contributing technical insights

What You Bring

• 6+ years of software or product engineering experience

• Strong experience building and scaling production systems

• Comfort with backend engineering (NodeJS, Postgres, TypeScript)

• Strong understanding of LLM application development patterns (RAG, prompt engineering, consistency testing) - either through production experience or demonstrated personal projects. If you're new to LLMs but have shipped complex production systems in other domains and are comfortable rapidly learning new technologies, we'd still love to hear from you.

• Ability to operate autonomously in a small, high-velocity team

• Excellent communication and collaboration skills

• Some experience with Kubernetes or distributed systems

It is a plus if you also have:

• Experience working on AI-driven or data-heavy products

• Frontend experience (NextJS, React, TypeScript)

• Understanding of CRM data models or workflow automation

This role may not be for you if you:

• Need lots of structure or long‑term roadmaps

• Prefer perfect specs before building

• Focus narrowly on backend or frontend only

This role is definitely not for you if you:

• Prefer fully remote work (this role requires at least 3 days a week in the office)

• Don’t enjoy the pace of early‑stage startups

• Want to manage a team rather than build

What We Offer

We will do our best to offer you a ride of a lifetime. It will not be easy, but it will be thrilling.

• Salary: £110,000 – £150,000 + equity

• 24 days holiday per year + bank holidays

• £450 Monthly Office Dinner Allowance

• 2 weeks work-from-anywhere

• Generous parental leave policy

• Pension plan

• Top-spec equipment and central London office

• Team events and dinners

• Work directly with the founders to scale the systems that power enterprise AI

• High-autonomy, high-trust environment with a small team shipping at pace

Tech Stack

• Back-end (AWS): NodeJS, TypeScript, Postgres

• Front-end: NextJS, TypeScript, Tailwind

• Workflow automation: n8n

Visas & Relocation

We sponsor visas for exceptional candidates and provide relocation support for those moving to London.

Interview Process

Stage 1: Introductory Call (40 minutes)

Stage 2: Hiring Manager Call (40 minutes)

Stage 3: Take-Home Task (≤ 2 hours)

Stage 4: Technical Interview (90 minutes)

Final Stage: Founders Interview - a conversation with Anders (CEO) and Marcus (CTO) focused on values alignment and long‑term vision.

Following Mutual Fit: Reference checks and offer stage.