Senior Backend Software Engineer at Series B circular economy startup

This job is brought to you by Jobs/Redefined, the UK's leading over-50s age inclusive jobs board.

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 Backend Software Engineer

Company Description: Series B circular economy startup

Job Description:
You will join a high-growth product engineering team building the digital infrastructure for a massive, traditionally offline global trade. Reporting to the CTO, you will own core marketplace features from discovery to payments, integrating proprietary AI engines into the user experience to manage high-volume inventory at a global scale.

Location: London, UK

Why this role is remarkable:

• Join a hyper-growth venture that is tripling in size annually while solving complex supply chain and sustainability challenges.
• Work at a Series B stage company backed by world-class tier-one VCs and prominent industry operators.
• Tackle unique engineering problems where every inventory item is one-of-a-kind, requiring innovative approaches to search and transactions.

What you will do:

• Architect and scale backend systems that handle hundreds of thousands of unique items monthly.
• Collaborate with AI and data teams to bridge advanced classification models with the core marketplace product.
• Take end-to-end ownership of the ecommerce journey, including checkout systems, seller tools, and order management.

The ideal candidate:

• Holds 3-6 years of professional backend experience, ideally using TypeScript and Node.js in consumer-facing environments.
• Possesses a product-driven mindset with the ability to connect technical architecture to commercial outcomes and user experience.
• Thrives in high-velocity startup environments and is comfortable navigating ambiguity to build systems from the ground up.

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.