Senior Full Stack Software Engineer

🔒 Confidential Employer
Posted 28 April 2026
LOCATION
London
TYPE
Full-time
LEVEL
Mid-Senior level
SALARY
£130,000 / year
CATEGORY
Technology
This employer holds a UK Home Office sponsor license — sponsorship for this specific role is at the employer’s discretion

SKILLS

React TypeScript JavaScript Python C# .NET Java C++

FULL DESCRIPTION

Senior Full Stack Software Engineer

Company: [Employer hidden — view at passion-project.co.uk]

Location: London, Paris

Salary: €60-130k

Work Type: Hybrid (2-4 days a week in office)

Job Type: Full-time

Experience Level: Senior and Expert level

About the Role

We are looking for a senior fullstack software engineer to work on real-time data synchronisation on large datasets, and display them on our "Excel on Steroids" app. We provide powerful tools to our clients so they can have a better overview of their business by numbers. It implies calculating and synchronizing large datasets that must be updated in real time. Our clients models can hold a few hundreds of thousands of lines (soon up to millions).

Our Engineering team is responsible for developing our SaaS platform and building a comprehensive and user-friendly product. [Employer hidden] engineers participate in the entire application development lifecycle, focusing on design, coding and keeping the production platform up and running. They can be specialized, but there is no strict separation between the backend and the frontend. We value user-centricity and pragmatism: we choose the most relevant tools for the problem we have to solve, understanding the strengths and constraints of each technology.

Who you are

  • More than knowledge of a specific language or framework, we are looking for great software engineering skills: ability to translate functional requirements into an elegant and simple design, and then deliver the code.
  • We are also looking for engineers who understand the product and the customer's needs in detail and can suggest innovative ideas: in the end, it's all about delivering value to end users.
  • Proven experience designing object oriented software with languages such as C#, Java, C++, Golang, Rust, Python or Ruby (this list is not exhaustive).
  • Proven experience with JavaScript, CSS and JavaScript libraries or frameworks such as React, Vue.js or Angular.
  • Great team spirit with a problem-solving attitude.
  • A good dose of humility and the willingness to grow (no matter your seniority!).
  • A fluent level in English (French is not a must).

Our technical stack

  • C# on .NET Core Linux
  • React
  • TypeScript
  • PostgreSQL
  • Google Cloud Platform
  • Docker
  • Kubernetes
  • Terraform
  • RabbitMQ
  • Circle CI

Company Information

Company Size: 201-500 employees

Industry: Fintech, B2B, Enterprise, Internal tools, Big data, Business Intelligence, SaaS, Data Analysis, Environmental, eCommerce

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