My client, a high-growth AI-native startup based in Central London, is looking for an exceptional Senior Backend or Full-Stack Engineer to join their core engineering team.
This is a rare opportunity to join an engineering-led company at an early but high-traction stage, working directly on business-critical AI and communications infrastructure used in real-world production environments.
The company operates as a genuinely AI-native engineering organisation. AI tooling, LLM-powered workflows, and rapid iteration are deeply embedded into how the team builds products day-to-day. The engineering culture is highly execution-focused, fast-moving, and extremely hands-on.
They are specifically looking for engineers operating at roughly Meta E5/E6 level (or equivalent from companies such as Meta, WhatsApp, Shopify, Stripe, Revolut, Deliveroo, etc.) with strong product engineering instincts and deep technical ability.
The ideal candidate is a highly capable senior engineer who combines startup velocity with strong systems thinking and enjoys operating in high-ownership environments.
You will work directly alongside the CTO (ex-JP Morgan) and Head of Engineering (ex-Meta) on core architecture, product direction, and scaling challenges.
Requirements:
• 5+ years of software engineering experience in high-performance production environments
• Strong backend or full-stack engineering skills
• Experience building scalable distributed systems and production infrastructure
• Strong product engineering mindset with ability to move quickly and own features end-to-end
• Experience with TypeScript / Node.js strongly preferred
• Experience with modern frontend frameworks (React / Next.js) is a plus for full-stack candidates
• Strong understanding of system design, reliability, scalability, and observability
• Experience in startups or fast-paced product environments is highly desirable
• AI-native mindset — comfortable leveraging AI tooling and rapid iteration workflows
• Strong communication skills and ability to operate autonomously
• European language skills required (Spanish strongly preferred)
• Must already have right to work in the UK or Europe — visa sponsorship is not available outside Europe
• Must be willing to work fully onsite from the company’s Central London office
Tech Environment:
• TypeScript, Node.js, React, Next.js
• AI-native workflows and internal LLM tooling
• Distributed systems and real-time infrastructure
• OpenSearch, SingleStore, Trigger.dev, Axiom
• Modern cloud-native infrastructure and observability stack
What they offer:
• Excellent compensation + meaningful equity
• High-ownership environment with direct impact on product and architecture
• Small, elite engineering team
• Direct collaboration with experienced leadership (ex-Meta / ex-JP Morgan)
• Centrally located Marylebone office
• Premium gym membership
• Fast-moving, ambitious startup environment with strong backing
This role is ideal for engineers who want to build quickly, solve difficult technical problems, and help shape the foundations of a high-growth AI company from an early stage.
To apply, please send your CV or contact gala.santaballa@mondrian-alpha.com directly.
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