Lead Backend Engineer

trg.; Greater London; Hybrid; GBP 90,000 - 120,000; Full time

Job summary

trg. in London is seeking a Lead Backend Engineer to stay hands-on with Python while managing a small team of 3–5 engineers. You will help shape technical direction for Scenario Builder, a platform used for energy-system modelling and decarbonisation analysis.

The role emphasizes leadership without losing code focus, working across data-heavy backend systems, APIs, cloud infra, and CI/CD to deliver real-world climate impact.

Qualifications

• 7+ years of back-end software development experience.
• Strong Python backend experience.
• Experience with FastAPI, Django or Flask.
• Comfort with PostgreSQL, APIs, cloud infrastructure and CI/CD.
• Technical leadership or line-management experience.
• Mentoring engineers while coding.
• Interest in climate or energy systems.

Responsibilities

• Lead a small team of 3–5 engineers and set technical direction.
• Stay hands-on with Python while guiding architecture.
• Improve backend systems and scale the Scenario Builder platform.
• Collaborate on data-heavy backend workflows and APIs.
• Balance engineering standards with pragmatic delivery.

Skills

Python

Backend development

APIs

PostgreSQL

Cloud infrastructure

CI/CD

Leadership

Mentoring

Code reviews

Tools

FastAPI

Django

Flask

Job description

Lead Backend Engineer — Climate Tech Nonprofit

London Hybrid — 2 days in London / 3 remote

Climate impact · Energy-system modelling · Backed by major philanthropic funders

I’m working with a climate-tech nonprofit building software that helps countries plan cleaner, more reliable electricity systems.

This isn’t a standard CRUD backend role.

The team is building Scenario Builder — a platform used for energy-system modelling, grid planning, decarbonisation analysis and long-term infrastructure decisions.

The engineering problems are genuinely interesting: data-heavy backend systems, performance challenges, APIs, infrastructure, modelling workflows and computational problems that have real-world climate impact.

They’re now looking for a Lead Backend Engineer who can stay hands‑on with Python while managing a small team of 3–5 engineers.

This is not a big-company Backend Lead IC role. It’s more of a hands‑on backend squad lead position where you’ll set technical direction, improve backend systems, coach engineers and help scale the platform behind Scenario Builder.

Could be a strong fit if you:

• 7+ years of experience in back-end software development
• Have strong Python backend experience
• Have worked with FastAPI, Django or Flask
• Are comfortable with PostgreSQL, APIs, cloud infrastructure and CI/CD
• Have some technical leadership or line-management experience
• Enjoy mentoring engineers while still staying close to the code
• Care about climate, energy systems or software with real-world impact
• Can balance strong engineering standards with pragmatic delivery

This is a good opportunity for someone who wants more ownership, a stronger leadership path and engineering work that matters beyond commercial optimisation.