Software Developer Sr

Dayforce

2d•Hybrid

About The Position

Our HR API Platform is the foundation of the Dayforce product—powering critical workflows that impact over 7,100 customers and process more than 2 billion API requests annually. As a Senior Software Developer (HR API Platform), you will play a key role in evolving this foundation to meet the demands of a modern, real-time, multi-region SaaS ecosystem. This includes handling complex inbound and outbound integrations, ensuring low-latency performance, and enabling scalable, event-driven architectures. You’ll work within a fast-moving, high-performance engineering team with strong technical standards and real ownership. Engineers here design, build, and operate their services end-to-end—and have a direct influence on both technical and product decisions. This is a chance to solve meaningful, large-scale problems in a domain that matters: ensuring people get paid accurately and on time. The systems you build will have a direct, daily impact on millions of users.

Requirements

Strong expertise in C# and modern .NET (Core/.NET 8+)
Deep experience building and optimizing RESTful APIs at scale
Strong understanding of distributed systems, microservices architecture, and cloud-native design
Proven ability to diagnose and improve performance (profiling, bottleneck analysis, memory/CPU optimization)
Experience with relational databases (e.g., SQL Server) and query optimization
Proficiency with modern JavaScript frameworks (React, Angular, or Vue) for full-stack collaboration
Experience with unit, integration, and performance testing frameworks
Hands-on experience with concurrency, async programming, and high-throughput systems
Solid understanding of API security (OAuth2, OpenID Connect, rate limiting, threat mitigation)
Experience building and operating services in cloud environments (AWS, Azure, or GCP)
Familiarity with containerization and orchestration (Docker, Kubernetes)
Experience with messaging/event systems (Kafka, RabbitMQ, or similar)
Knowledge of caching layers (Redis, CDN strategies)
Experience with CI/CD pipelines and DevOps practices
Strong observability mindset (OpenTelemetry, Prometheus, Grafana, etc.)
Familiarity with API gateways and service mesh concepts
Practical experience using tools like GitHub Copilot and/or Claude Code to improve productivity
Ability to critically evaluate AI-generated code for correctness, security, and performance
Strong collaboration skills in Agile environments
Excellent communication and documentation abilities
Self-starter mindset with a focus on ownership and outcomes
Proficiency in English is required for this position as this role will regularly interact with English-speaking stakeholders, co-workers, managers and/or clients across the world. Further, our back office support teams, including but not limited to Human Resources, are primarily English speaking. Employees need to be able to communicate with these departments in English to appropriately administer their business relationship. Due to the significant high volume of interactions with these English-speaking co-workers, managers, stakeholders and/or clients, which is inherent to this position, it is not possible to reorganize the company's activities to avoid this requirement.

Nice To Haves

Experience designing and operating high-availability public API platforms at enterprise scale
Experience with GraphQL in production environments
Background in platform engineering or developer experience (DX)
Experience with multi-region deployments and global traffic management