Job Description:

INTRODUCTION

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

Bath & West Community Energy is recruiting two practical full-stack developers to build the Home Energy Efficiency Advice Tool (HEEAT), a new platform combining energy modelling, mobile data capture, smart-meter data and applied AI.

The technology stack includes Python, FastAPI and PostgreSQL on the backend, with React, React Native and TypeScript on the frontend, deployed on AWS or a similar cloud platform. AI-assisted capture, extraction, validation and report drafting will sit alongside deterministic, tested and auditable energy calculations.

One appointment will have deeper frontend strength and the other deeper backend and data-platform strength. These are complementary rather than narrowly siloed roles, and we will balance skills across the two appointments. Candidates may apply for the frontend-focused role, the backend-focused role or either role using one application.

BWCE is a not-for-profit community energy organisation with 17 MW of community-owned renewable generation and a home-energy advice service that has delivered more than 500 surveys. The developers will work with Technical Lead Philip Haile, home-energy assessors and project partners across Great Britain.

Applicants must already be resident in the UK and have the right to work in the UK. We cannot provide visa sponsorship.

TASKS

Frontend-focused Full-Stack Application Developer

• Build React and TypeScript interfaces for surveys, assessments, scenario editing and reporting.

• Develop floorplan, room-geometry, image-supported, LiDAR and canvas or SVG editing workflows.

• Design mobile-first capture using React Native or similar, followed by desktop analysis.

• Create usable forms, validation, guidance and warnings that maintain data quality.

• Connect the frontend to FastAPI services and make straightforward backend changes where established patterns exist.

• Build AI-assisted capture and review features into the survey workflow.

• Make complex modelling outputs understandable to professional assessors and householders.

Backend-focused Full-Stack Data Platform Developer

• Build reusable Python and FastAPI services with clean, documented API contracts.

• Design PostgreSQL schemas, migrations, indexing and data-validation patterns.

• Develop ingestion pipelines for weather, tariff, carbon, smart-meter, billing and product data.

• Own authentication, permissions, audit trails, encryption and secrets management.

• Establish Git workflows, continuous integration and deployment, versioning and releases.

• Operate cloud environments, backups, monitoring, alerting and security hardening.

• Integrate LLM and machine-learning services behind structured, validated and auditable interfaces.

• Implement deterministic modelling workflows, background jobs, logging and operational tooling.

What you will build

HEEAT will take an assessor from an in-home survey to a completed report. It will combine guided phone and tablet data capture, smart-meter and billing data, Home Energy Model calculations, heat-pump, solar PV, battery and tariff analysis, and automated reporting and quality assurance.

The platform will be modular, cloud-hosted and released as open source, with documented APIs so that other organisations can reuse its modelling and data services. Core energy calculations will remain deterministic, tested and auditable, while bounded AI features support capture, extraction, validation and report drafting.

PROFILE

We are recruiting complementary frontend-focused and backend-focused developers. We do not expect each candidate to cover everything below; we are interested in your strongest area and will balance skills across the two appointments.

For the frontend-focused role

• Substantial professional experience developing applications with React and TypeScript.

• Experience integrating frontend applications with backend APIs.

• Working Python experience, ideally with FastAPI or a similar framework.

• Good judgement about usability, validation, errors and edge cases.

• Understanding of authentication, permissions and safely handling personal data in frontend applications.

For the backend-focused role

• Substantial professional experience in Python backend development, ideally using FastAPI or a similar framework.

• PostgreSQL and relational data-modelling experience.

• Experience designing documented APIs and data-validation patterns.

• Cloud deployment and monitoring experience, ideally with AWS or a similar platform.

• Practical knowledge of authentication, authorisation, application security and protecting personal data.

• Enough React and TypeScript experience to make straightforward changes and diagnose integration problems.

For both roles

• Experience building maintainable production software using Git, pull requests, continuous integration, code review, typed APIs and automated testing.

• Numerical confidence and the ability to turn quantitative domain logic into reliable, tested software.

• Critical and productive use of AI coding tools, with proper review of their output.

• Clear communication, pragmatic technical judgement and an interest in climate, homes and community benefit.

Useful additional experience

Useful additional experience includes React Native; offline or field workflows; maps; canvas or SVG editing; floorplans; image processing or LiDAR; infrastructure as code and cloud operations; open-source development; LLM, multimodal AI or machine-learning services in production; and domestic energy, building performance, heat pumps, solar PV, batteries or smart-meter data.

WE OFFER

Remote working within the UK, flexible working and flexible hours, approximately 0.7–1.0 FTE, 25 days’ annual leave plus bank holidays pro rata, an employer pension contribution, and the option to join the company healthcare plan following completion of the three-month probationary period.

ADDITIONAL INFORMATION

Eligibility

Applicants must already be resident in the UK and have the right to work in the UK. We cannot provide visa sponsorship.

Why join HEEAT

This is a greenfield development offering substantial ownership, technical depth and potential national impact. You will work with energy modelling, smart-meter data, heat-pump optimisation, mobile data capture, applied AI and automated reporting, as part of a two-developer team with a hands-on Technical Lead who continues to write code.

You will begin with a two- to three-day in-person induction near Bath, covering the home-energy domain and the existing modelling approach.

Start date

Between December 2026 and January 2027, with early January preferred.

How to apply

Read the complete role profiles and download the BWCE application form at:

https://www.bwce.coop/current-vacancies

Submit the completed application form, including the requested project examples, together with your CV. State whether you wish to be considered for the frontend-focused role, the backend-focused role or either role. No separate covering letter is required.

Applications close at 9.00am on Monday 9 November 2026.

BWCE is committed to equality of opportunity and welcomes applications from suitably skilled candidates from all backgrounds. We are happy to discuss flexible working and any adjustments needed during recruitment.