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
Only candidates based in UK and eligible to work in UK are allowed