Senior .NET Performance Engineer in London

servicePath™ is an innovative provider of commercial software for IT Service Providers, specifically managed Services and Cloud Computing providers. We are strong proponents of leveraging Artificial Intelligence to drive innovation, aligning with our core value of continuous improvement. By integrating AI into our workflows, we enhance productivity, streamline processes, and elevate our solutions to new heights.

We are looking for a Senior .NET Performance Engineer to own the runtime health and throughput characteristics of our platform. This is a specialist contributor role — you won't be building feature logic, you'll be ensuring the systems that run it do so efficiently, reliably, and at scale.

Our platform handles complex revenue lifecycle calculations across large contract datasets, with high-throughput data pipelines and long-running services that demand careful memory management and tuning. If your instinct when something feels slow is to open a profiler rather than add a cache, this role is for you. At servicePath™, we seek candidates who are eager to enhance performance by leveraging tools and technologies like AI. Our goal is to streamline tasks, increase efficiency, and maximize productivity, making work more manageable while driving organizational success.

Key Responsibilities:

• Profile, diagnose, and resolve performance bottlenecks across .NET services — from GC pressure and memory leaks to thread contention and I/O saturation
• Own memory management strategy across long-running services — heap allocation patterns, LOH fragmentation, finaliser queues, and GC tuning (gen0/1/2, server vs. workstation, DATAS)
• Investigate and optimise high-throughput data pipelines — batch processing, streaming patterns, buffer management, and backpressure handling
• Identify and resolve large dataset query performance issues — index utilisation, query plan analysis, pagination strategies, and aggregation efficiency across both relational and document databases
• Establish and maintain performance benchmarking infrastructure using BenchmarkDotNet and load testing tooling — define baselines, track regressions, and gate releases on performance criteria
• Conduct performance-focused code reviews — identify allocations, boxing, closure captures, LINQ misuse, and other common .NET performance anti-patterns
• Collaborate with product engineers to surface performance constraints early in design, without blocking feature delivery
• Produce clear diagnostics and findings documentation that non-specialists can act on

Key Competency and Experience:

• 5+ years of .NET / C# development with a demonstrable specialism in performance engineering
• Deep, hands-on experience with .NET profiling tools — dotMemory, dotTrace, PerfView, Visual Studio Diagnostic Tools, or equivalent
• Strong understanding of .NET memory management internals — GC generations, LOH, pinned objects, finalisation, and how allocation patterns affect runtime behaviour
• Experience optimising high-throughput data processing pipelines — including async/await patterns, Channel<T>, pipelines, and avoiding synchronisation bottlenecks
• Proven ability to diagnose large dataset query performance issues across both relational (SQL) and document databases, including index analysis and query plan interpretation
• Familiarity with ETW, EventPipe, and diagnostics tooling (dotnet-trace, dotnet-counters, dotnet-dump)
• Strong benchmarking discipline — BenchmarkDotNet, reproducible test conditions, and regression tracking
• Ability to communicate findings clearly across engineering teams

Core Competencies:

• Deep diagnostic instinct
• Low-ego specialist mindset
• Clear written communication
• High ownership
• Comfortable working independently across a distributed team

Preferred:

• Experience with RavenDB or other document databases at scale — including index optimisation, bulk operations, and storage engine behaviour under load
• Familiarity with Span<T>, Memory<T>, ArrayPool, and other low-allocation patterns introduced in modern .NET
• Background in financial, billing, or revenue platform engineering where calculation correctness and throughput are both non-negotiable
• Experience with distributed systems performance — service mesh latency, serialisation overhead, connection pooling, and inter-service call optimisation

Coordinate with Product Manager / Owner: Yes, on Daily Basis (Daily Stand Ups)

If you are an existing employee interested in applying for this role, please submit your resume and reach out to your HR representative for a confidential discussion and guidance on the next steps.

Background Checks and Ethical Conduct:

servicePath™, conducts background checks as part of its hiring process. We take integrity seriously, fraudulent misrepresentation, identity deception, or unauthorized subcontracting will result in withdrawal of an offer or termination.

Equal Opportunity Employer:

At servicePath™, we are proud to be an equal opportunity employer, dedicated to fostering a diverse and inclusive workplace where everyone is valued and respected. We make all employment decisions based on merit, without regard to race, gender, religion, nationality, sexual orientation, disability, or any other protected characteristic. We celebrate and support diversity, recognizing it as a strength that enhances our work environment and drives our success.