Senior Engineer - Backend and AI Infra

Salary range£100,000-£150,000 p.a. + equity, depending on experience (up to £170,000 for candidates with exceptional relevant experience)

How to applyEmail us at work@writewithmarker.com and tell us a little bit about yourself and your interest in the future of writing, along with your CV or a link to your CV site.

What is Marker?Marker is an AI-native Word Processor – a reimagining of Google Docs and Microsoft Word.

Join us in building the next generation of agentic AI assistants supporting serious writers in their work.

We are a small, ambitious company using cutting-edge technology to give everybody writing superpowers.

What you\''ll do at Marker

Develop our bespoke agentic assistant execution platform (TypeScript)

Build and integrate systems for retrieval, search, observability, multi-modal generation, and more

Maintain model evaluation suites to optimise for quality, cost and reliability

Deploy and operate stateful workloads on our cloud infrastructure (AWS)

Contribute to our real-time collaborative application backend (Cloudflare Workers, TypeScript, CRDTs, PostgreSQL)

Be a part of the early founding team to guide the future of our products and company at large

What we can offer

A calm, human-friendly work environment among kind and experienced professionals

Fun, creative, novel, and interesting technical work (if you\''re into that sort of thing)

An opportunity to work with and learn about the latest advancements in AI engineering and language models

As much responsibility and growth opportunities as you want to take on

Are you a good fit for this role?In order to be successful in this role, you will recognise yourself in the following:

You have at least a few years of experience building non-trivial backend systems and enjoy writing code in TypeScript

You keep up to date with the latest developments in AI engineering, and have already worked with LLMs

You are interested in building novel and innovative backend systems requiring creativity, problem-solving and research

You\''re not afraid of contributing frontend codebases when needed

You\''re willing to write Python when necessary

You\''re familiar with some of the other technologies in Our Stack (see below)

An exceptional candidate for this role would be able to demonstrate some of the following:

Experience using and operationalising language models in production, especially in multi-agentic systems

Experience in deploying and scaling stateful compute workloads using Docker, Kubernetes, Pulumi or other IaC approaches

Experience in observability tooling and devops practices

Experience with collaborative real-time technologies (CRDTs, Y.js, sync engines, etc.)

Interest in writing (fiction, non-fiction, essays)

However, you are NOT expected to:

Be an expert in AI, NLP, or Machine Learning

Have solved every possible problem with agentic AI systems before — it’s a new and rapidly evolving field, and we are discovering and solving novel problems every day

Be experienced with every library and product in our stack from day one — you’ll work closely with our engineering lead Jani Eväkallio to learn the ropes and design future systems together

Have a degree in Computer Science — we value practical experience over credentials

Our stackYou''ll be working with the following technologies:

Our AI engine uses a range of models, including self-hosted and fine-tuned open source models, as well as latest reasoning models from Anthropic and OpenAI

Our agentic AI execution platform is written in TypeScript, hosted on Cloudflare Workers. We build heavily on Durable Objects and Workflows.

Our real-time application backend is built with Cloudflare Workers, Durable Objects, CRDTs and PostgreSQL.

Our text editor frontend is a web application built with React, TypeScript and ProseMirror

Apply now!Interested? Email us at work@writewithmarker.com with your CV (or a link to your CV site). Tell us a little bit about yourself and why you\''d like to work at Marker!

Please note that this role is currently only available based in our London hub, and at this time we are not able to sponsor work visas in the ..... full job details .....