Senior Software Engineer - .NET, C# & APIs

Canada - Toronto · CAD 118,000-152,000 · 8+ years experience · Posted Oct 15, 2026

At a glance

Capco is seeking a Senior Software Engineer with strong expertise in C#, .NET, ASP.NET Core, and API development to join our Technology & Engineering practice in Toronto.
In this role, you will design, develop, modernize, and maintain enterprise applications and APIs that support business-critical solutions for our clients.
We are looking for an experienced, hands-on engineer who brings strong backend development capabilities, an understanding of modern frontend frameworks, and experience delivering secure, scalable, and reliable software.

Design, develop, and maintain scalable backend services and enterprise applications using C#, .NET, ASP.NET Core, and SQL Server.
Build, enhance, and integrate secure RESTful APIs, including authentication, authorization, data validation, and error handling.
Contribute to the modernization of existing applications, including refactoring legacy code, improving performance, and enhancing system reliability.
Work across the application stack, collaborating on frontend development using React, Angular, or similar JavaScript/TypeScript frameworks.
Apply secure coding principles and API security practices, including OAuth2, JWT, and common application security standards.
Participate in technical design discussions, code reviews, automated testing, troubleshooting, and performance optimization.
Support CI/CD pipelines, containerized deployments, and development workflows using tools such as Docker.
Collaborate with engineers, product teams, and quality specialists to deliver high-quality solutions in Agile environments.
Leverage AI-assisted development tools responsibly to support coding, testing, debugging, and documentation while maintaining security and engineering standards.
Share technical knowledge and contribute to continuous improvements in development practices and software quality.

8+ years of professional software engineering experience, with strong hands-on development expertise in C# and .NET.
Solid experience building and maintaining applications using ASP.NET Core, Web API, and RESTful services.
Strong understanding of backend architecture, API design, system integrations, and object-oriented programming principles.
Experience working with SQL Server or comparable relational databases, including data access technologies such as Entity Framework Core or Dapper.
Experience with modern frontend development using React, Angular, or similar JavaScript/TypeScript frameworks.
Understanding of application security principles, including authentication, authorization, OAuth2, JWT, and secure coding practices.
Experience working with Git, code reviews, automated testing, CI/CD pipelines, and Agile software delivery.
Strong problem-solving and troubleshooting skills, with the ability to investigate and resolve complex technical issues.
Ability to collaborate effectively with cross-functional teams and communicate technical concepts clearly.

Experience modernizing legacy .NET applications or migrating enterprise systems to modern architectures.
Exposure to Azure or AWS cloud environments, Docker, Kubernetes, or cloud deployment troubleshooting.
Experience with performance optimization, application monitoring, and production support.
Familiarity with accessibility standards such as WCAG or AODA.
Experience with Snowflake, data warehouses, or enterprise data integrations.
Experience with Tailwind CSS, shadcn/ui, or other modern frontend component libraries.
Experience using AI-assisted software development tools such as GitHub Copilot, ChatGPT, or other AI-powered coding and testing solutions.
Experience mentoring developers, contributing to technical documentation, or improving engineering standards.

Comprehensive Benefits Coverage – 100% company-paid health, life, and disability insurance effective from Day 1 of employment.
Retirement Savings Program – Registered Retirement Savings Plan (RRSP) with the option of receiving a matching employer contribution.
Virtual Health Care and Employee & Family Assistance Program (EFAP) available to employees and their dependents/partners.
Parental Leave Top-Up, New Parent Gift, and Wellness Support including fitness reimbursement benefits.

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