Applications Test Engineer Salary: Competitive Salary| Derby - Onsite | Contract - 6 months initially | Flexible Working Security Clearance: Minimum SC clearance required and have it cleared already; DV highly desirable We're recruiting for a Applcations Test Engineer to join a growing and ambitious team at a pivotal stage in its journey. Want to be part of a business that is disrupting the national security market? Our client is a fast-growing UK sovereign technology company delivering innovative encryption and secure communications solutions to some of the country's most demanding customers. Combining deep technical expertise with an agile, customer-focused approach, they are challenging the status quo and proving that world-class capability can come from a dynamic and ambitious SME. What We're Looking For: * 5+ years’ commercial experience in software or applications testing. * Strong experience testing Windows desktop applications, ideally within a .NET environment. * A solid understanding of functional, system, regression and integration testing. * Experience writing and executing structured test cases and test procedures. * Strong skills in defect investigation, troubleshooting and root cause analysis. * Experience testing UI/UX, user workflows and application functionality. * Good networking knowledge across TCP/IP, routing, switching, VLANs, DHCP, DNS and VPNs. * Practical understanding of SNMP and network device management. * Experience using Wireshark or similar packet-analysis tools. * Strong written and verbal communication skills, with the ability to produce clear technical documentation and test reports. * A methodical, analytical approach and excellent attention to detail. * The ability to work independently while collaborating effectively with software developers and engineering teams. Key Responsibilities: * Create, review and maintain test plans, test procedures and test cases for Windows desktop applications. * Plan and execute functional, system, regression and integration testing. * Test applications used to configure, monitor and manage secure networking devices. * Validate software requirements and ensure requirements traceability throughout the development lifecycle. * Assess UI, UX and end-to-end user workflows to ensure applications are intuitive, reliable and fit for purpose. * Identify, reproduce, investigate and document software defects and technical issues. * Perform troubleshooting and root cause analysis, working closely with developers and engineers to resolve issues. * Validate communications between software applications and network-connected hardware. * Test SNMP functionality and network device management features. * Analyse network traffic and communications using Wireshark and similar tools. * Record test results, observations and defects accurately and maintain clear technical documentation. * Support software releases, acceptance testing and customer-facing validation activities. * Contribute to improving testing processes, methodologies and quality standards. * Support the development of automated testing and contribute scripting or automation ideas where appropriate. * Work collaboratively with software developers, systems engineers and product stakeholders to ensure high-quality software delivery. What's on offer: -25 days annual leave -Company pension -4x Death in service -EV car scheme -Benefit platform with high street discounts If you have the experience we are looking for and you think you will succeed within this industry and role, apply today