Senior Backend Developer with Umbraco C# .net

Onyx-Conseil; Greater London; On-site; GBP 55,000 - 75,000; Full time

Job summary

Onyx-Conseil in London is seeking a Senior Backend Developer to own the eCommerce web and internal applications, focusing on ASP.NET, C#, Umbraco, and cloud deployment.

You will lead development from a technical perspective, collaborate with frontend and design teams, automate testing and improvements, and contribute to a high‑quality, scalable platform.

Qualifications

• Extensive experience with ASP.NET/C# and front-end tech; solid SQL/NoSQL knowledge.
• Strong understanding of Umbraco CMS and cloud deployment patterns.
• Experience with CI/CD pipelines and automated testing practices.

Responsibilities

• Lead ecommerce web and app development from a technical perspective.
• Collaborate with frontend and design to enhance UI/UX.
• Analyze and improve existing features and automate processes.
• Implement automated regression testing and quality assurance.

Skills

ASP.NET

C#

HTML

JavaScript

jQuery

React

MS SQL Server

MongoDB

Elasticsearch

SOLID principles

Umbraco CMS

Continuous Delivery

Azure

Git

Github

Jenkins

Selenium

TeamCity

Octopus

Swagger/OpenAPI

REST APIs

JSON/XML/SOAP

PowerBI

PowerQuery

R

TDD/BDD

Agile/Kanban

Jira

Confluence

Tools

Git

Github

Jenkins

TeamCity

Octopus

Selenium

Job description

Senior Backend Developer with Umbraco C# .net

Working as part of the Digital team, you'll be responsible for the ongoing development and improvements to an eCommerce website as well as other internal applications for this award-winning Travel Company.

You will be responsible for:

Leading the eCommerce web and application development from a technical perspective

• Collaborating with the front end developer and design resource to deliver improved UI & UX
• A problem solver - you'll need to be able to analyse and suggest improvements to existing website features
• Analysing and identifying ways to automate processes working alongside the business lead
• Implementing automated regression testing for the software developed

Skills and Experience:

• Excellent working knowledge of ASP.NET, C#, HTML, JavaScript, jQuery, React Framework, MS SQL Server, Mongo DB, Elasticsearch
• Understanding of SOLID development principles
• Worked previously on projects using the Umbraco CMS
• Continuous Delivery skills, tools and techniques (e.g. Git, Github, Team City, Octopus, Jenkins, Selenium, etc.)
• Familiar with Azure cloud services & setting up/managing resources/deploying apps
• Familiar with JIRA and Confluence
• Capable of working with (and developing) multiple (REST) APIs documented with e.g. OpenAPI/swagger and other API messaging formats e.g. JSON, XML, SOAP
• Experience of PowerBI, PowerQuery and R
• Experience of structured testing and quality assurance approaches (e.g. Test Driven Development and Behaviour Driven Development)
• A positive and cooperative individual who will work effectively across departments and within a team
• Worked in an agile/Kanban environment and familiar with JIRA and confluence
• Not afraid to challenge existing thinking in order to improve processes

The salary for this role will be in the range £55K to £75K per year depending on experience.

The Client is based in Central London and this role will be working remotely.