Application Support Engineer | £40-£50K

Their platform comprises three core applications: built on a .NET/VB.NET/C# stack with SQL Server, deployed across both Azure-hosted and on-premise (Windows Server) customer environments.

You'll work shoulder-to-shoulder with the engineering team - confirming genuine defects, providing detailed technical reproduction steps, and occasionally contributing fixes yourself for well-understood issues. This is a hands-on technical role for someone who enjoys getting into the guts of a complex enterprise application.

What You'll Be Doing:

Own escalated tickets from 1st line support requiring deeper technical investigation

Write and run SQL Server queries against production and test databases to investigate data integrity issues, configuration problems, and reported bugs.

Read and step through VB.NET/C#/.NET Framework and .NET codebase to understand root cause, distinguishing genuine defects from configuration or user error.

Reproduce complex, intermittent, or environment-specific issues across ASP.NET WebForms, MVC, and newer Vue.js/SPA application.

Troubleshoot SOAP and REST API integration issues raised by customers connecting third-party or ERP systems

Investigate issues at the infrastructure level - Windows Server (2019/2022), IIS, and SQL Server configuration - across both Azure-hosted and on-premise customer environments.

Monitor and respond to production alerts via Site24x7

Log well-evidenced defects into Jira with clear reproduction steps, logs, and impact assessment, and track them through to resolution and release.

Proven experience in a 2nd line/technical support/application support role, ideally supporting a complex B2B or enterprise software product.

Strong working knowledge of SQL Server - confident writing non-trivial queries (joins, aggregations).

Ability to read and reason about C# and/or VB.NET code to identify root cause

Practical understanding of ASP.NET applications (WebForms and/or MVC)

Comfortable working with Windows Server environments - troubleshooting application, IIS, and OS-level issues.

Experience with API troubleshooting - inspecting SOAP or REST requests/responses (eg via Postman, SoapUI, or browser dev tools)

Marlow - £40-£50K Full Time Posted by: SmartSourcing Ltd Posted: Thursday, 2 July 2026 Application Support (.Net/SQL) Hybrid/Marlow 3 days per week on site Up to 50K

Our client provides enterprise-grade Field Service Management (FSM) platform, serving multi-vertical service operations across fire security, facilities management, HVAC, medical devices, and MoD/defence supply chain customers in the UK, Ireland, and internationally.

SmartSourcing Ltd offers contract, permanent, fixed term and outcome based work package opportunities across Digital and Technology, Transformation, Project and Programme Management, PMO, Business Change, Cloud Services, Cyber Security and wider corporate functions. Our experienced team works closely with candidates throughout the recruitment process, from initial engagement and role matching through to pre interview preparation, onboarding, timely payments and ongoing assignment support. We are committed to clear and personal communication, professional representation and a service led approach that helps candidates find the right opportunity for their skills, experience and career goals