Key skills
Software DevelopmentPerformance OptimizationC#PythonASP.NET.NET Application Performance TuningScriptingJavaScriptProfiling ToolsSQL ProfilerdotTraceDebugDiagWinDbgFiddlerDatabase Performance TuningMS SQLMongoDBMicroservicesDistributed System DesignAPI PerformanceObservability ToolsAppDynamicsOpenTelemetryDatadogPrometheusGrafanaAI Tools IntegrationCSQL.NETAIKubernetesDockerSaaSJiraCI/CDCommunicationCollaboration
About this role
Dayforce is a global human capital management company headquartered in Toronto and Minneapolis. They are seeking a Senior Performance Engineer focused on optimizing application performance through code-level analysis and collaboration with engineering teams to ensure scalability and efficiency.
Responsibilities:
- Profile, analyze, and optimize application code to improve:Execution efficiencyCPU, memory, and I/O utilizationLatency and throughput
- Conduct deep-dive investigations into performance issues using tools such as:SQL Profiler, dotTrace, DebugDiag, WinDbg, Fiddler, and observability platforms
- Identify and resolve performance bottlenecks at the code, database, and system level, leveraging profiling data, logs, and telemetry
- Analyze and optimize:C# / ASP.NET application performance (threading, async patterns, memory usage, GC behavior)
- Database queries and execution plans (MS SQL, MongoDB)
- Network calls and API behavior
- Collaborate with developers and architects to:Embed performance considerations into system design
- Influence architectural decisions for scalability and efficiency
- Drive performance-focused code reviews
- Optimize enterprise SaaS applications across:Multi-tier web architectures
- Microservices-based distributed systems
- Design and execute capacity and scalability experiments to guide system sizing and cost optimization
- Build and enhance tools to monitor, analyze, and visualize performance metrics in cloud environments
- Analyze performance data and provide clear, actionable recommendations to engineering and product stakeholders
- Leverage AI tools to automate analysis, optimize workflows, and improve engineering productivity
- Contribute to and lead performance engineering best practices across teams
Requirements:
- Strong background in software development with a focus on performance optimization
- Proficiency in one or more programming languages: C# and Python
- Strong experience with: ASP.NET / .NET application performance tuning and diagnostics
- Experience with scripting and automation: Python, JavaScript
- Deep hands-on experience with profiling and debugging tools, such as: SQL Profiler, dotTrace, DebugDiag, WinDbg, Fiddler
- Strong experience with code-level profiling and optimization techniques
- Hands-on experience with database performance tuning: MS SQL, MongoDB (query optimization, indexing, execution plans)
- Proven ability to: Analyze and optimize code for quality, efficiency, and performance
- Diagnose complex performance issues in distributed systems
- Solid understanding of: Microservices and distributed system design
- API performance and service interactions
- Experience with observability and performance monitoring tools, such as: AppDynamics, OpenTelemetry, DBA Dash, Datadog, Prometheus, Grafana
- Experience working with engineering workflows and tracking systems such as Jira
- Demonstrated ability to integrate AI tools to optimize/redesign workflows and drive measurable impact
- Strong collaboration and communication skills, with the ability to influence technical decisions
- Experience with performance testing tools (e.g., JMeter, Gatling, k6, LoadRunner)
- Familiarity with CI/CD pipelines and integrating performance validation into workflows
- Experience with containerization and orchestration (Docker, Kubernetes)
- Experience with advanced profiling techniques (e.g., flame graphs, heap analysis, thread dumps)
- Background in cloud cost optimization and efficiency engineering
- Experience with non-functional requirement (NFR) gathering and performance test planning