Dayforce is a global human capital management (HCM) company headquartered in Toronto, Ontario, and Minneapolis, Minnesota, with operations across North America, Europe, Middle East, Africa (EMEA), and the Asia Pacific Japan (APJ) region. Our award‑winning Cloud HCM platform offers a unified solution database and continuous calculation engine that drives efficiency, productivity and compliance for the global workforce.

About the Opportunity

We are seeking a Senior Performance Engineer with a strong software engineering background and deep expertise in profiling, debugging, and optimizing application performance at scale. This developer‑first role focuses on improving system efficiency through code‑level analysis, architectural insights, and data‑driven optimization. You will work closely with engineering teams to identify performance bottlenecks, optimize execution paths, and ensure our platforms are highly scalable, reliable, and cost‑efficient.

What You'll Get to Do

- Profile, analyze, and optimize application code to improve execution efficiency, CPU, memory and I/O utilization, latency 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, garbage‑collection 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, and 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 explicit, 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.

Skills and Experience We Value

- Strong background in software development with a focus on performance optimization.
- Proficiency in one or more programming languages, primarily C# and Python.
- Strong experience with ASP.NET / .NET application performance tuning and diagnostics.
- Experience with scripting and automation using Python and JavaScript.
- Deep hands‑on experience with profiling and debugging tools such as SQL Profiler, dotTrace, DebugDiag, WinDbg, and Fiddler.
- Hands‑on experience with database performance tuning for MS SQL and 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, Datadog, Prometheus, and Grafana.
- Experience working with engineering workflows and tracking systems such as Jira.
- Demonstrated ability to integrate AI tools to optimize redesign workflows and deliver measurable impact.
- Strong collaboration and communication skills, with the ability to influence technical decisions.

What Would Make You Really Stand Out

- Experience with performance testing tools such as JMeter, Gatling, k6, and LoadRunner.




- Familiarity with CI/CD pipelines and integrating performance validation into workflows.
- Experience with containerization and orchestration using Docker and Kubernetes.
- Advanced profiling techniques such as flame graphs, heap analysis, and thread dumps.
- Background in cloud cost optimization and efficiency engineering.
- Experience with non‑functional requirement gathering and performance test planning.

What’s in It For You

Dayforce encourages personal and professional growth. We offer excellent time‑off programs, comprehensive wellness initiatives, competitive pay and benefits, and a commitment to community impact through volunteer days and charitable giving. Our focus is on supporting you to be the best version of yourself.

Dayforce is an equal‑opportunity employer and welcomes individuals of all backgrounds and identities. We believe in diversity, equity, and inclusion, and encourage individuals to apply based on their passions.

Artificial intelligence may be used in the screening, assessment, or selection of applicants for this position.

About the Salary Ranges

The salary range mentioned in this job description is a guide; the final compensation offered may vary based on bonuses, incentives, candidate experience, skills, budget, and location. Dayforce is committed to providing a fair, equitable, and competitive package that reflects the value an individual brings.

Proficiency in English is required for this role, as it involves frequent interaction with English‑speaking stakeholders, co‑workers, managers, and clients worldwide. Employees must communicate effectively in English with back‑office support teams and across departments.

Fraudulent Recruiting Notice

Beware of fraudulent recruiting. Legitimate Dayforce contacts will use an @dayforce.com email address. We do not request money, checks, equipment orders, or sensitive personal data during the recruitment process. If you suspect a fraudulent contact, please reference our recruiting fraud statement on Dayforce’s website.

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📌 Performance Engineer Sr (Toronto)
🏢 Dayforce
📍 Toronto