Full-Stack Developers – Frontend and Backend Focus (Two Roles)

Build open-source software that helps households cut bills and carbon.

Bath & West Community Energy is recruiting two full-stack developers to build the Home Energy Efficiency Advice Tool (HEEAT):

• Full-Stack Application Developer – Frontend Focus React · React Native · TypeScript · Python · FastAPI · Applied AI

• Full-Stack Data Platform Developer – Backend Focus Python · FastAPI · PostgreSQL · React · Cloud Infrastructure · Applied AI

These are not two rigidly separated positions. We are building a small, collaborative development team and will balance frontend and backend skills across the two appointments. You can apply for the frontend-focused role, the backend-focused role or either role using one application.

About HEEAT

HEEAT is a new open-source platform designed to take an energy assessor from an in-home survey through to modelling, recommendations and a completed household report.

It will bring together guided mobile data capture, smart-meter and billing data, building-energy modelling, heat-pump optimisation, solar PV, batteries, energy tariffs and automated reporting.

Good whole-home energy advice is currently expensive and time-consuming to deliver. HEEAT aims to make it faster, more consistent and more affordable, allowing community organisations across Great Britain to help many more households reduce their energy bills and carbon emissions.

This is a greenfield project with no production legacy code. The underlying assessment method has been developed and tested in more than 100 homes, but the development team will make important decisions about the production architecture and implementation.

The roles

The frontend-focused developer will lead the user-facing web and mobile application, including in-home survey capture, building and scenario editors, modelling results and reports.

You should be strong in React and TypeScript and comfortable working across the API boundary, including typed schemas, validation, integration tests and straightforward FastAPI changes.

The backend-focused developer will lead the backend and data platform, including Python and FastAPI services, PostgreSQL, data ingestion, authentication, security, engineering workflow and cloud operations.

You should be strong in Python and backend or data architecture and able to debug frontend integration and build straightforward administrative interfaces in React.

Across the two roles, the work will include:

• Building React and TypeScript interfaces for surveys, assessments, scenario editing and reporting.
• Developing mobile-first data-capture and building-editing tools involving floorplans, room geometry, photographs and interactive canvas or SVG components.
• Building reusable Python and FastAPI services with clean, documented API contracts.
• Designing PostgreSQL schemas, migrations, indexing and data-validation patterns.
• Developing ingestion pipelines for weather, energy tariffs, carbon intensity, smart-meter, billing and product data.
• Implementing deterministic energy-modelling and optimisation workflows.
• Establishing Git, pull-request, testing, CI/CD, versioning and release processes.
• Managing authentication, permissions, audit trails, encryption and secrets.
• Running cloud environments, deployment, backups, monitoring and security hardening.
• Integrating bounded AI features for capture support, data extraction, validation and report drafting while keeping core energy calculations deterministic, tested and auditable.

The stack

Python, FastAPI and PostgreSQL on the backend; React, React Native and TypeScript on the frontend; deployed on AWS or a similar cloud platform.

We use AI coding tools as a serious productivity aid, with normal engineering review. HEEAT itself will include bounded AI features, but its core calculations will remain transparent and auditable.

Why join us?

• Build a technically interesting greenfield product with genuine climate impact.
• Work across energy modelling, smart-meter data, heat pumps, solar PV, batteries and tariffs.
• Take meaningful ownership within a small development team.
• Build reusable open-source infrastructure for community organisations.
• Work directly with energy assessors as your first users and testers.
• Work alongside a hands-on Technical Lead who developed the prototypes and underlying modelling and continues to write code.

Terms

Salary: £45,000–£70,000 FTE, paid pro rata depending on skills and experience.
Hours: Around 0.8 FTE, flexible between 0.7 and 1.0 FTE.
Location: Remote-first and UK-based, with occasional meet-ups in Bath or Cambridge/Royston.
Contract: Fixed term to autumn 2028, approximately 21–22 months. We are seeking funding to continue beyond this stage.
Start: January 2027, with a December 2026 start possible.
Interviews: Remote, with evening times available.
Application deadline: 9am on Monday 9 November 2026.

Applicants must be resident in the UK and already have the right to work in the UK.

How to apply

Visit https://www.bwce.coop/current-vacancies for the complete job profiles and BWCE application form.

Please submit the completed application form, including the requested project examples, together with your CV. Indicate whether you are applying for the frontend-focused role, the backend-focused role or either.

We are more interested in evidence of thoughtful, working software than keyword-heavy CVs. If you cannot share commercial code, describe the architecture, trade-offs, testing approach and your own contribution instead.

A community-owned not-for-profit energy organisation developing renewable energy, home energy services and open-source tools to help reduce household bills & carbon emissions.