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- Tasks: Drive performance improvements in applications and infrastructure while collaborating with diverse teams.
- Company: Fully remote role with a forward-thinking tech company focused on innovation.
- Benefits: Competitive day rate, flexible working hours, and potential for contract extension.
- Why this job: Make a real impact by optimising performance and enhancing user experience at scale.
- Qualifications: Strong background in performance engineering and hands-on expertise in .NET and SQL Server.
- Other info: Join a dynamic team with opportunities for professional growth and skill development.
Location: Fully Remote (UK)
Day Rate: £400-£450 per day (Inside IR35)
Contract Length: 6 months (Possible Extension)
We’re looking for an experienced Senior Software Engineer (Contract) to join on an interim basis and drive performance improvements across our applications and infrastructure. You’ll be responsible for identifying bottlenecks, putting the right telemetry in place, and helping our teams deliver a faster, more reliable experience for customers at scale.
Key Must Have Skills:
- .NET (C#), DOM performance
- JavaScript
- MS SQL Server, query optimisation, and indexing strategies
- K6, Playwright, AppInsights
- Azure DevOps - CI/CD pipelines and observability tooling
What you’ll be doing:
- Front-end performance: Investigate and optimise browser behaviour, including JavaScript execution, rendering, and DOM interactions.
- Backend performance: Analyse .NET applications for efficiency, memory usage, and concurrency, implementing improvements where needed.
- Database tuning: Optimise SQL queries, indexes, and overall database performance.
- Instrumentation & monitoring: Expand and refine telemetry across the stack using tools such as AppInsights, K6, and Playwright.
- Collaboration: Partner with engineers, testers, and product teams to prioritise performance initiatives, share best practices, and influence long-term improvements.
- Load testing: Support the design and execution of realistic load/performance scenarios to uncover weaknesses and recommend fixes.
What we’re looking for:
- Strong background in performance engineering across browser, server, and database layers.
- Hands-on expertise with:
- JavaScript profiling and browser internals.
- .NET (C#), async programming, concurrency, and memory management.
- SQL Server query tuning and indexing.
- Familiarity with modern observability and testing tools (e.g. K6, Playwright, AppInsights, Azure DevOps).
- Good knowledge of CI/CD practices and performance instrumentation.
Nice to have:
- Experience working with Vue.js or other modern front-end frameworks.
Senior Software Engineer (Contract) employer: Digital Waffle
Contact Detail:
Digital Waffle Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Senior Software Engineer (Contract)
✨Tip Number 1
Network like a pro! Reach out to your connections in the tech world, especially those who might know about opportunities in performance engineering. A friendly chat can often lead to job leads that aren’t even advertised.
✨Tip Number 2
Show off your skills! Create a portfolio or GitHub repository showcasing your projects, especially those involving .NET, JavaScript, and SQL Server. This gives potential employers a taste of what you can do and sets you apart from the crowd.
✨Tip Number 3
Prepare for interviews by brushing up on your performance engineering knowledge. Be ready to discuss how you've tackled bottlenecks and optimised applications in the past. We want to see your problem-solving skills in action!
✨Tip Number 4
Don’t forget to apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we love seeing candidates who are proactive about their job search.
We think you need these skills to ace Senior Software Engineer (Contract)
Some tips for your application 🫡
Tailor Your CV: Make sure your CV highlights your experience with .NET, JavaScript, and SQL Server. We want to see how your skills match the role, so don’t be shy about showcasing your performance engineering expertise!
Craft a Compelling Cover Letter: Your cover letter is your chance to shine! Tell us why you’re passionate about performance improvements and how you’ve tackled similar challenges in the past. Keep it engaging and relevant to the job description.
Showcase Your Projects: If you've worked on projects that involved load testing or database tuning, make sure to mention them! We love seeing real-world examples of your work, especially if they relate to the tools we use like K6 or AppInsights.
Apply Through Our Website: We encourage you to apply directly through our website. It’s the best way for us to receive your application and ensures you’re considered for the role. Plus, it’s super easy!
How to prepare for a job interview at Digital Waffle
✨Know Your Tech Inside Out
Make sure you brush up on your .NET (C#), JavaScript, and SQL Server skills. Be ready to discuss specific performance improvements you've implemented in the past, especially around query optimisation and memory management. This will show that you not only understand the theory but have practical experience too.
✨Showcase Your Problem-Solving Skills
Prepare to talk about how you've identified bottlenecks in applications before. Think of examples where you've used tools like AppInsights or K6 to monitor performance and how you turned those insights into actionable recommendations. This will demonstrate your analytical mindset and hands-on approach.
✨Collaboration is Key
Since this role involves working closely with engineers, testers, and product teams, be ready to share experiences where you've successfully collaborated on performance initiatives. Highlight how you’ve influenced long-term improvements through teamwork and communication.
✨Practice Makes Perfect
Before the interview, run through some common technical questions related to performance engineering. You might even want to simulate a load testing scenario or discuss how you would approach optimising a slow application. This will help you articulate your thought process clearly during the actual interview.
