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Jack & Jill

Senior Software Engineer

Hybrid

London, United kingdom

Senior

Full Time

10-02-2026

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Skills

Python Go Rust PostgreSQL Monitoring Machine Learning Autonomy Analytics

Job Specifications

This is a job that Jill, our AI Recruiter, is recruiting for on behalf of one of our customers.

She will pick the best candidates from Jack's network

The next step is to speak to Jack.

Senior Software Engineer

Company Description: Well-funded Series B AI startup

Job Description:

You will architect and build the backend for high-performance systems managing billions of data points. This role involves scaling infrastructure to handle massive volumes of unstructured data for machine learning workflows. Working with a veteran team, you will ensure the platform remains fast and reliable as the company enters a stage of hyper-growth.

Location: London, UK

Why this role is remarkable:

Join a high-performing engineering team including ex-founders and veterans from elite tech firms
Impact the frontier of multi-modal AI by building the core infrastructure for data curation and indexing
Benefit from a culture of high autonomy, end-to-end ownership, and rapid career progression during expansion

What you will do:

Design and maintain performant systems using a modern stack including Python, Rust, and Clickhouse
Take full ownership of projects from initial architectural decisions through to deployment and monitoring
Solve complex scaling challenges related to querying and manipulating massive datasets at global scale

The ideal candidate:

Extensive experience building and maintaining large-scale, reliable backend systems from the ground up
Deep technical proficiency with PostgreSQL and column-oriented analytics systems like Clickhouse
A builder mindset that thrives on solving technical ambiguity with simple, maintainable, and robust solutions

Who are Jack & Jill?

Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.

And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.

Next steps

Step 1. Visit our website

Step 2. Click 'Talk to Jack'

Step 3. Talk to Jack so he can understand your experience and ambitions

Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role

Step 5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction

Step 6. If not, Jack will find you excellent alternatives. All for free

We never post fake jobs

This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.

Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.

We appreciate this can make them look a bit suspect, but there isn't much we can do about it.

Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.

About the Company

Ok, I'll go first. I'm Jack, an AI that gets to know you deeply, what you’re great at and what you want out of your career. I then work to make that a reality – finding the best fit public job listings as they come up, supporting with applications, interview prep, and moral support. I also work together with my partner Jill to find off-market opportunities and introduce you directly to companies, just like a recruiter would. And I'm Jill, an AI that spends time with hiring managers and talent teams to really understand their... Know more