Founding Software Engineer

About Marble

Marble is a climate tech venture studio. We partner with scientists, engineers, and operators to create companies solving hard climate problems in the world's largest industries.

Our first 15 companies are building transformative products across energy, industry, agriculture, and climate resilience. 100% have been successful in raising follow-on to date. We are looking to partner with exceptional individuals to create our next venture.

Empowering the Trades

The UK’s 885,000 construction micro-businesses deliver £49bn of small construction projects each year. Most run on WhatsApp, spreadsheets, and memory. The unstructured approach costs roughly 20% of each job in scope drift, rework, untracked changes, and delayed compliance.

The industry is also highly wasteful, with 13% of materials never being used and construction accounting for 61% of the UK’s landfill. We are reliant on this highly fragmented industry to refurbish our buildings to meet performance needs and the targets of the Climate Change Act. However, at current rates, it will take 100+ years to decarbonise the UK’s built environment.

We are building an AI-native operating system for independent installers to ease administrative burden, reduce project costs, and accelerate business growth. Our technology empowers tradespeople to grow their business, gain professional independence and administrative efficiency. By de-risking installations for both the contractor and the customer, we will enable the UK to cost effectively scale delivery across millions of buildings.

About the Role

You will be the primary driver of product delivery and implementation of the technical architecture. You will report to the CEO and be the technical voice in product, hiring, and strategy decisions. This is not a role where someone hands you a detailed step by step, specification and you implement it. You will work directly with installers and the team to turn their needs into working software solutions.

Core Responsibilities

• Architecture ownership: Own the full technical stack including: Ionic Angular / React, FastAPI services, Supabase (Postgres, Auth, Storage), Cloudflare Workers, and LLM integrations.

• Shipping software: Write, test, and deploy code. This is a hands on product role, not a management role. At Pre-Seed, the founding engineer is the engineering team.

• AI/LLM integration: Ship LLM powered capabilities to augment installer workflows from surveying, scoping, quoting and documenting compliance. Train CNNs to recognise features.

• Product collaboration: Work directly with installers and our customer success lead, hear what they need, and make the decisions that turn those needs into working software. Understand the trade well enough to make good judgment calls when the spec is ambiguous, and to push back when a requested feature would not actually solve the underlying problem.

• Technical decision-making: Work with the team to choose tools, libraries, and patterns. Decide what to build, what to buy, and what to defer. Advise on technical hiring as the team grows.

Requirements

You are a strong fit if you recognise yourself in most of the following:

Skills

• Software engineering fundamentals: Solid CS foundations including data structures, algorithms, systems design, testing, architecture.

• Full-stack web and mobile: You ship production apps from front end to back end. Experience with component-based frameworks and mobile apps real users depend on.

• Python backend: Comfortable building APIs, data pipelines, and service integrations in Python. Familiarity with FastAPI, Django, or Flask is useful but not essential, what matters is that you can design clean, testable services.

• AI/LLM agentic workflows: You've built production AI processes including agent first workflows, RAG, structured output parsing and understand the gap between a demo and a production-level system.

• Cloud infrastructure: You can deploy, monitor, and maintain apps end-to-end on modern cloud platforms (Supabase, Cloudflare, AWS, or similar).

• Data modelling: You design schemas that evolve with the product without quarterly rewrites.

Behaviours

• Product over features: You measure output in customer outcomes, not code shipped. You'd rather spend a morning with an installer than refactoring if that's where the learning is.

• Builder mentality: Ship imperfect on Thursday over perfect next month but you track technical debt, communicate it, and know when it's dangerous. At Pre-Seed, learning speed is the primary engineering metric.

• Full-picture comfort: No hard lines between front end, back end, infra, and product. You go where the work is.

• Ownership: You own the CI pipeline, the migration, the failing test, and the customer bug. There's no one to delegate to during the Pre-Seed stage.

• Clear communication: You explain technical trade-offs in plain language and flag risks early.

Bonus Points

• You have built multi-tenant SaaS applications.

• You have worked with Ionic, Angular, or the Capacitor/Cordova ecosystem.

• You have designed AI workflows with human-in-the-loop review gates.

• You have worked with CNN’s and Computer Vision.

• You have built or contributed to developer tools, internal platforms, or infrastructure automation.

• You have a strong appreciation for design and UX.

• You understand UK construction compliance (MCS, Part P, Building Regulations).

What we Offer

As a founding technical lead, you will partner with the current Founder in Residence who has been developing this project as CEO over the last 12 months. The founder has 20+ years of product development experience in the construction industry, ML and Computer Vision. Most recently, he was responsible for an AI powered quality assurance system used by automotive OEMs, and before that built and scaled a robotic tool and installer operating system that delivered over 5,000 installs with zero compliance failures.

We offer (among other things):

• Contract: This role can begin as fractional (2–3 days per week) with a clear path to full-time, or start full-time from day one. We will discuss what works for both sides. Based in, or near Bristol or Exeter with regular co-located working in the South West.

• Salary: Competitive for Pre-Seed stage, discussed openly during the process.

• Equity: Significant early-stage equity. This is a founding-team role and the equity reflects that.

• Autonomy: Real ownership of the tech stack and product direction. You will shape the company, not just work for it.

• Mission: Direct, measurable impact on how independent tradespeople run their businesses and contribute to the UK’s net-zero transition.

• Tools: Modern development and AI tools, a founder who has built and exited twice before, and a product roadmap shaped by over 100 installer interviews.