AI Engineer (Staff/Principal) in London

About Us: Fifth Dimension is bringing vibe working to document-heavy industries. Today we work with real estate businesses in the US, EU and APAC, automating complex tasks, extracting valuable insights from documents, and empowering professionals to focus on high-impact work. Our AI workspace transforms how large investment managers and developers handle leases, development documents, and investment decisions. We're a London and New York based startup with an ample runway, backed by Tier 1 European and American investors. Our founders, Johnny Morris and Dr. Kate Jarvis bring a powerful blend of expertise: Johnny has 17+ years applying data and analytics to Real Estate, while Kate holds a Stanford PhD and 12 years of executive experience across Silicon Valley and London startups.

At Fifth Dimension, we're demanding yet encouraging, valuing experimentation and kind challenges. Our company values, Own It, Ship It, and Don't Be Boring, drive us to deliver exceptional results while fostering a culture of innovation and continuous improvement.

The Challenge: It's 9 AM on a Monday. Using Claude Code, you've just implemented a new extraction pipeline that transforms how property leases are analyzed. By noon, a major real estate firm emails: "This just saved us 40 hours of work." By Thursday, you're troubleshooting with their development team as they integrate your APIs into their enterprise document management system. By Friday, you're celebrating with the team as data flows seamlessly between platforms, unlocking new capabilities for real estate investors that will help them make faster, more informed decisions across their portfolios.

About You: You're an expert software engineer who has witnessed the transformative power of AI and wants to apply it to solve real business problems. You don't just code—you architect solutions that make users say "How did we ever work without this?" You've developed exceptional engineering and architectural skills through years of practice. You stay current with AI advances and can identify the right approach for each unique challenge. Your experience implementing AI in business contexts has taught you that the magic isn't in the model—it's in understanding the problem deeply.

You're proficient with AI coding assistance tools like Claude Code, leveraging them to accelerate development and focus on higher-level architectural challenges. You understand that modern engineering means effectively collaborating with AI to maximise your productivity and creative potential. Details don't escape you. You're comfortable diving into complex documents and intricate code to build a complete picture. As someone who thrives in fast-paced environments, you adapt quickly and mentor other engineers while collaborating effectively with commercial teams and customers.

You're passionate about your personal growth and see each complex problem as an opportunity to expand your capabilities. You actively seek challenges that push the boundaries of what's possible and value environments where you can both contribute your expertise and continue to evolve as an engineer.

Your Impact: Reporting to our CTO Chen, you'll architect and implement innovative AI technology to meet our enterprise customers' unique needs. Working closely with our skilled engineering team, you'll design scalable AI solutions that deliver tangible value and expand the capabilities of our generative AI platform. You'll own the complete lifecycle of core product capabilities from initial customer conversations through architecture, implementation, deployment, and customer adoption.

Day to Day, You Will:

• Think like a Product Manager: Own core product components while balancing technical excellence with business impact.
• Own end-to-end delivery of complex features from initial concept to production deployment and customer adoption.
• Collaborate with product and commercial teams to understand customer needs and translate them into robust technical solutions.
• Leverage AI coding tools like Claude Code to accelerate development workflows.
• Lead development of features solving our customers' most complex challenges:

• Advanced data extraction systems for processing property leases at scale.
• Sophisticated workflow automation for analyzing planning documents and drafting advice.
• Multi-step agentic content generation for creating market research reports.

Our Values and Engineering Culture: At 5D, we embody three core principles: Own it, Ship it, and Don't be boring. Our engineering team values:

• Product-Minded Engineering: Understanding the "why" behind features and using technical expertise to inform product decisions.
• Intellectual Honesty: Backing discussions with data and acknowledging knowledge gaps.
• Effective Time Management: Setting clear timebox and abandoning approaches that aren't working.
• Clear Communication: Writing self-documenting code and providing detailed explanations.
• Innovation Mindset: Forming well-reasoned opinions backed by data and continuously learning.
• Personal Growth: Supporting your development through challenging work and opportunities to expand your expertise.

Intellectual Curiosity and Honesty in Action: An Example: Here's an example of how we work: Early in our journey with AI, one of our engineers discovered that certain words like "concise" or "creative" had disproportionate effects on model outputs—we called them "demon words." Rather than accepting this as an immutable quirk, they spent a week methodically tracking down every instance in our codebase, testing alternatives, and documenting the patterns they found. This intellectual curiosity to understand the "why" behind technical oddities, combined with the honesty to admit what we didn't yet understand, led to significant improvements in our product's reliability. At 5D, we value this combination of curiosity and honesty above all—the willingness to dive deep into unexpected behaviors and openly share both successes and failures with the team.

What We're Looking For:

• Experience in high-growth startups or fast-paced tech environments.
• Track record building software in organizations with excellent engineering practices.
• History of owning end-to-end product development, from definition to delivery and customer adoption.
• Strong Python skills with a track record of shipping customer-facing features on critical paths.
• Experience building and maintaining high-quality APIs and integrations.
• Proficiency with AI coding assistance tools (Cursor, GitHub Copilot, Claude Code).
• Intellectual curiosity and honesty—digging deep into problems and sharing findings openly.
• Proven ability to make technical decisions that balance immediate user needs with long-term architecture.
• Exceptional communication abilities for explaining complex concepts to diverse audiences.
• Ambition and resilience—we're a seed-stage company tackling ambitious challenges.
• Commercial awareness—delivering continuous value to customers is essential.
• Passion for personal growth and continuous learning.

Nice to Have (But Not Required):

• Past experience in real estate, law, or finance.
• Background with robust software testing and deployment practices.
• Experience with component-based system design and microservices.
• Contributions to open-source projects or broader technical communities.

What we offer you: We're building something extraordinary and we want extraordinary people. Our benefits package goes beyond the standard startup offering—from tailored support for life's challenges (IVF, gender-affirming care, ADHD diagnosis, and more), to meaningful parental leave.

£100,000-160,000 salary per annum + meaningful equity (on a standard vesting schedule).

Enhanced Pension Contributions - 5%.

Unlimited annual leave.

£100 monthly well-being budget.

Tailored support for exceptional challenges. This looks different for everyone, but can include contributions to:

• Gender-affirming care.
• Private specialist and scans for an injury.
• ADHD / Autism diagnosis.
• IVF.
• Therapy.

Enhanced Parental Leave: 14 weeks full pay (followed by standard statutory pay) for primary caregiver; 6 weeks full pay for secondary caregiver.

Electric Car Scheme (salary sacrifice).

£1000 annual training budget.

The process: Submit your CV, along with answers to the handful of questions we ask of every candidate. A call with our CTO to explore the initial fit. A live task and competency interview. An in-person culture fit interview with a range of people across the business, including the 2 founders. Alternatively, we offer a paid-for one-week trial for candidates who are available for the setup.