Application Support Engineer

Application Support (.Net/SQL) Hybrid/Marlow 3 days per week on site Up to 50K (maybe negotiable)

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.

About the Role

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. They are a strategic 'Spearhead' product, with active investment in a UX/UI overhaul, migration to Azure PaaS, and ongoing feature development.

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 across Service Centre, REA, and RCA.
• 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 Tesseract's 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 components of the application.
• Troubleshoot SOAP and REST API integration issues raised by customers connecting third-party or ERP systems to Tesseract.
• 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, carrying out first-level infrastructure diagnostics ahead of escalation to platform/engineering teams.
• Log well-evidenced defects into Jira with clear reproduction steps, logs, and impact assessment, and track them through to resolution and release.

What You’ll Need:

Essential

• Proven experience in a 2nd line / technical support or 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) to investigate data and configuration issues.
• Ability to read and reason about C# and/or VB.NET code to identify root cause, even without day-to-day development responsibility.
• Practical understanding of ASP.NET applications (WebForms and/or MVC) and how they're deployed under IIS.
• Comfortable working with Windows Server environments — troubleshooting application, IIS, and OS-level issues.
• Experience with API troubleshooting — inspecting SOAP or REST requests/responses (e.g. via Postman, SoapUI, or browser dev tools) to isolate integration issues.
• Strong analytical and diagnostic skills — able to work methodically from symptom to root cause on ambiguous or intermittent issues.
• Excellent communication skills, comfortable explaining technical findings to both customers and engineers.

What They’ll Offer You:

Competitive salary

Pension - 5% company contribution, 3 % personal contribution

Private Healthcare via BUPA

A holiday allowance of 30 days', plus bank holidays per annum

Employee Assistance Program (EAP)

Electric car scheme

Cycle to work scheme

Enhanced Maternity/Paternity Pay

Our client is an equal-opportunity employer and values diversity in its workforce. We encourage applicants from all backgrounds to apply.

SmartSourcing are a Disability Confident Employer and we promote, celebrate and value diversity, we are committed to promoting equality and inclusion for all.