Senior Software Engineer I

OneStream Software delivers a unified Corporate Performance Management (CPM) platform designed to meet the complex financial, operational, and analytical needs of large enterprises. The Senior Software Engineer designs, develops, and delivers complex features and services within OneStream solutions, ensuring well-designed APIs and data contracts while mentoring junior engineers and leading cross-functional collaborations.

Responsibilities:

• Design, develop, and maintain complex software features and services within OneStream, including requirements translation, technical design, implementation, validation, deployment, and ongoing production support
• Lead implementation efforts for moderately to highly complex features, ensuring scalability, performance, maintainability, and reliability
• Drive technical design discussions and contribute to architectural decisions aligning with platform standards and reference architectures
• Build and maintain user interface solutions using modern UI frameworks including Angular, React, Blazor, and WPF
• Make and defend technical decisions within owned areas while aligning with broader architectural standards
• Ensure JSON and XML data contracts, schemas, and integrations are well designed, documented, and backward compatible
• Design and evolve APIs, SDKs, and extensibility mechanisms used by internal teams and partners
• Proactively identify opportunities to improve system performance, reliability, and developer productivity
• Lead and participate in formal code reviews, act as a trusted reviewer and approver
• Mentor and support Software Engineers through guidance on design, coding standards, and best practices
• Collaborate cross-functionally to translate business requirements into technical solutions and proactively identify opportunities to improve system performance, reliability, and developer productivity
• Contribute to CI/CD improvements, automation, testing strategies, and overall engineering quality initiatives
• Own complex features and components end to end, including design, implementation, testing, deployment, and ongoing production support
• Use AI-assisted development tools to accelerate development, refactoring, test creation, and documentation, while critically evaluating and refining AI-generated output to ensure correctness, security, performance, and architectural alignment
• Partner with peers to diagnose and resolve production issues, ensuring system reliability and performance

Requirements:

• Bachelor's degree in Computer Science, Engineering, or a related technical field, or equivalent experience
• 4-10 years of professional software development experience
• Strong proficiency in C#, .NET, and ASP.NET, and related frameworks
• Experience building user interfaces with modern UI frameworks including Angular, React, Blazor, and WPF
• Deep understanding of RESTful API design and service-oriented architectures
• Strong experience designing, maintaining, and evolving JSON contracts in enterprise applications
• Experience with performance tuning, memory management, and SQL query optimization
• Strong experience with Git-based workflows and CI/CD pipelines
• Experience reviewing unit tests and ensuring adequate test coverage
• Experience building extensible platforms, frameworks, or SDKs
• Familiarity with SaaS architectures, distributed systems, or multi-tenant applications
• Experience with deployment automation and DevOps practices
• Domain experience in financial systems, EPM, or CPM solutions
• Azure experience and/or relevant Azure certifications