Find a job 
Featured Companies 
Featured Universities 
For Companies At a Glance
- Tasks: Build the transaction layer for a revolutionary digital supply chain in secondhand fashion.
- Company: Join a $50M Series B AI-native marketplace backed by top investors.
- Benefits: Competitive salary, equity options, and a chance to shape the future of fashion.
- Other info: Collaborate with elite teams and see your work directly influence a $350B industry.
- Why this job: Make a real impact in a high-growth environment while saving millions of garments from landfills.
- Qualifications: 6–10 years backend experience with strong system design and API skills.
The predicted salary is between 100000 - 140000 £ per year.
You will join the Growth squad to build the transaction layer for the world’s first digital supply chain for secondhand fashion. Reporting to the CTO (ex-Google, Postmates), you will integrate fine-tuned AI models into a B2B marketplace handling 500,000+ items monthly, turning manual trades into a structured, searchable global inventory layer.
Location: London, UK
Why this role is remarkable:
- Work at the intersection of circular economy and proprietary AI, using a fine-tuned model (not a GPT wrapper) to digitize a $350B industry that has never had technology.
- Massive financial backing with ~$50M raised from elite investors including a16z, Y Combinator, and HV Capital, plus advisors from Depop and Shopify.
- High-velocity environment where you will see immediate impact, helping save millions of garments from landfills while the company triples in size year-on-year.
What You Will Do:
- Architect and scale backend systems in Node.js and TypeScript to handle the transition from 500k to millions of unique items per month.
- Own the end-to-end ecommerce journey, including discovery, search, checkout, and complex international payment and credit systems.
- Collaborate with AI and data teams to bridge the gap between classification engines and the core marketplace product experience.
The Ideal Candidate:
- 6–10 years of professional backend experience with strong fundamentals in system design and API architecture at high-growth consumer or marketplace companies.
- Proven product engineering mindset with a history of shipping end-to-end features in fast-paced, ambiguous startup environments.
- AI-forward builder who uses tools like Cursor or Copilot as a force multiplier and has experience deploying AI capabilities at scale.
Senior Backend Software Engineer (£100k–£140k + Equity) at $50M Series B AI-native marketplace in London employer: Jack & Jill
Contact Detail:
Jack & Jill Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Senior Backend Software Engineer (£100k–£140k + Equity) at $50M Series B AI-native marketplace in London
✨Tip Number 1
Network like a pro! Reach out to folks in the industry, especially those connected to the company you're eyeing. A friendly chat can sometimes lead to insider info or even a referral, which can give you a leg up.
✨Tip Number 2
Show off your skills! If you’ve got a portfolio or GitHub with projects that highlight your backend prowess, make sure to share it. Real-world examples of your work can speak volumes more than just words on a CV.
✨Tip Number 3
Prepare for the interview like it’s a big game! Research the company’s tech stack and be ready to discuss how your experience aligns with their needs. Practising common technical questions can also help you feel more confident.
✨Tip Number 4
Don’t forget to apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we love seeing candidates who take that extra step to connect with us directly.
We think you need these skills to ace Senior Backend Software Engineer (£100k–£140k + Equity) at $50M Series B AI-native marketplace in London
Some tips for your application 🫡
Tailor Your CV: Make sure your CV reflects the skills and experiences that align with the Senior Backend Software Engineer role. Highlight your backend experience, especially in Node.js and TypeScript, and any relevant projects that showcase your ability to handle high-growth environments.
Craft a Compelling Cover Letter: Your cover letter is your chance to shine! Use it to tell us why you're excited about working at the intersection of AI and the circular economy. Share specific examples of how you've contributed to similar projects in the past and how you can bring that expertise to our team.
Showcase Your Problem-Solving Skills: In your application, don’t just list your technical skills; demonstrate how you've used them to solve real-world problems. We love candidates who can think critically and creatively, so share stories that highlight your product engineering mindset and your experience in fast-paced environments.
Apply Through Our Website: We encourage you to apply directly through our website for the best chance of getting noticed. It’s the easiest way for us to keep track of your application and ensure it reaches the right people. Plus, we can’t wait to see what you bring to the table!
How to prepare for a job interview at Jack & Jill
✨Know Your Tech Stack
Make sure you’re well-versed in Node.js and TypeScript, as these are crucial for the role. Brush up on your system design and API architecture knowledge, and be ready to discuss how you've applied these skills in previous projects.
✨Showcase Your AI Experience
Since this role involves integrating AI models, be prepared to talk about your experience with AI tools and how you've deployed them in past projects. Highlight any specific examples where you’ve used AI to enhance backend systems or improve user experiences.
✨Demonstrate Your Problem-Solving Skills
Expect to face some technical challenges during the interview. Practice articulating your thought process when tackling complex problems, especially in high-growth environments. Use examples from your past work to illustrate how you’ve successfully navigated ambiguity.
✨Understand the Company’s Mission
Familiarise yourself with the company’s focus on the circular economy and its impact on the fashion industry. Be ready to discuss how your values align with theirs and how you can contribute to their mission of digitising a $350B industry.