Senior Fullstack Engineer (Python, NextJS)

Climate X; City Of London; Hybrid; GBP 50,000 - 80,000; Full time

Job summary

A technology firm in London is seeking a Senior Full Stack Engineer to work on systems integrating external customers. You will develop intuitive interfaces and maintain backend services, focusing on high performance and reliability. This role offers the opportunity to contribute to both frontend and backend projects, creating impactful solutions in a supportive team environment.

Benefits

Monthly training budget

Pension contribution scheme

Mental health support

25 days holiday plus Bank Holidays

Dog friendly office

Qualifications

• Experience developing and maintaining RESTful APIs.
• Strong background in working within cloud environments.
• Ability to implement responsive design and complex visualizations.

Responsibilities

• Develop and maintain APIs and services.
• Build user interfaces with NextJS.
• Collaborate with teams for frontend and backend integration.

Skills

Experience with Python

Strong proficiency in TypeScript

Understanding of REST APIs

Experience with complex workflows

Familiarity with AWS

Tools

Docker

Kubernetes

PostgreSQL

Job description

Senior Full Stack Engineer (Carta)

August 2025

About us

Climate X is a purpose-driven technology company, backed by GV (Google Ventures), Western Technologies (early investors in Meta, Google, Palantir), Commerz Ventures, Pale Blue Dot, Deloitte, and other world-class investors. We’re a wonderfully diverse, growing team with physical offices in London and New York City.

Demand for Climate X is growing fast, and we need to build our team! You’ll be at the front of a nascent industry, working as part of a fantastic and diverse team, doing things that you can be proud of. We’re excited to have the opportunity to speak with you during this process.

Our mission

To deepen the understanding of our changing planet and inspire meaningful action.

What we do

• We’re helping the world become more resilient to the impacts of physical climate risks (including floods, fires, storms and more). In doing so, we help drive positive global impact aligned to many of the UN’s Sustainable Development Goals (SDG’s).
• Our team builds cutting-edge, peer-reviewed science (incorporating climate projections, remote sensing data) and translates that into financial impacts (to the value of assets or business disruption linked to failure of critical infrastructure) that our customers in the financial services industry use to identify, manage and mitigate those risks.
• Climate X’s customers include the world’s largest banks, asset managers and insurance companies including CBRE, Standard Chartered, Virgin Money and Federated Hermes, as well as a partnership ecosystem that includes Deloitte, Capgemini and AWS. Combined, they manage over $6.5 trillion of assets.
• Customers choose us thanks to our ecosystem of products that help solve real human problems and drive tangible business benefits. They love our customer-centric mindset, as well as our pace of innovation in the market.

THE IMPACT YOU’LL OWN

As a Senior Full Stack Engineer in our Carta pod, you will work on systems that integrate with external customers and other internal systems to orchestrate the discovery and risk analysis of company asset datasets. You’ll build intuitive interfaces that enable our clients to efficiently map and analyse company assets while working on modelling the corporate network and their asset portfolios. You’ll create seamless integrations between frontend and backend services, ensuring high performance and reliability throughout the application stack.

This role will initially focus on backend observability and fact set development, working closely with our Machine Learning team. Over time, you\'ll have the opportunity to contribute to frontend UI enhancements for the platform and support other products such as Spectra and Adapt. We’re looking for someone who’s comfortable moving between projects, collaborating across teams, and working across the full stack—from backend systems to frontend interfaces.

• Backend Integration:
  • Develop and maintain RESTful APIs and services in Python and Typescript
  • Build robust workflows that orchestrate end-to-end business processes
  • Create efficient database schemas and queries
  • Model corporate networks and asset portfolios
  • Ensure proper error handling and service reliability
• Frontend Development:
  • Build responsive and intuitive user interfaces using NextJS
  • Implement complex data visualizations and interactive features
  • Optimize application performance and loading times
  • Ensure cross-browser compatibility and responsive design
  • Collaborate with UX/UI designers to implement design systems

ESSENTIAL SKILLS

• Experience with Python for supporting tools and applications
• Strong proficiency in TypeScript for both frontend and backend development
• Strong understanding of REST APIs and frontend-backend integration
• Experience with complex workflows (e.g. orchestration-based or event driven)
• Familiarity with cloud (AWS) and IaC (Terraform)

DESIRABLE SKILLS

• Experience with React and NextJS
• Test Driven Design (TDD)
• Experience with Temporal or similar (Celery, BullMQ, microservices, distributed systems)
• Experience with containerization (Docker, Kubernetes)
• Experience with LGTM stack/observability stack
• Experience with TailwindCSS
• Experience with PostgreSQL and PostGIS
• Understanding of CI/CD principles
• Experience with data visualization libraries
• Experience with automated testing and test-driven development
• Knowledge of responsive design principles and cross-browser compatibility

INTERVIEW PROCESS

1. Talent screening call (15-30 mins)
2. Cultural and technical interview (1 hour) [with Director of Engineering + wider teams]
3. Take-home technical challenge (1-2 hours)
4. Live technical interview following up from the work completed at home (1.5 hour) [with Staff Engineer/line manager + pod engineer]

We are flexible to host interviews online or in our London office

BENEFITS

Contribute to a business making purposeful impact related to climate change

Monthly training & conference budget to help you upskill and develop your career (£1,000 per year)

6 monthly appraisals and 12 monthly pay reviews

Pension contribution scheme

Hybrid working (3 days/week in office)

Mental Health and Wellbeing support via Oliva

25 days holiday, plus Bank Holidays, annual 3-day Christmas-closure, and half day on your birthday (36.5 days total!)

Optional quarterly socials, dinners, and fun nights out

A fully stocked supply of snacks, fruit, and refreshments for the days when you are in the office

Cycle to work scheme via gogeta

Enhanced maternity and paternity

Pawternity

Dog friendly office (official residence of Alfie, Chief Mischief Officer)

EQUAL OPPORTUNITIES

Climate X are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. We are committed to creating an inclusive environment for all employees and welcome applications from individuals of all backgrounds.