.NET Developer

Toronto, CanadaWestmount, Canada Until 8/23/2026 5+ years exp First posted March 18, 2026 Last posted March 18, 2026
Job description

About Rentsync:
Rentsync is an award-winning, high-growth organization that provides high quality websites, marketing services, and software solutions to the rental and property management industry throughout Canada and the United States.

About the Role

We’re looking for an experienced .NET Core Developer to help build and enhance modern, business-oriented applications. In this role, you’ll design and maintain scalable APIs, optimize server-side performance, and contribute to the ongoing evolution of our systems using Clean Architecture and modern C# patterns. You’ll collaborate closely with product, front-end, and QA teams to deliver secure, reliable, and efficient solutions. This is a great opportunity to work with cutting-edge tools and AI technologies while refactoring legacy systems and shaping the future of our platform.


Duties & Responsibilities

  • Develop, maintain, and optimize server-side logic and database structures.
  • Design and implement RESTful APIs and other web services to support front-end functionality based on a description from the product team.
  • Create and support existing unit and integration tests.
  • Participate in the refactoring of the legacy code (.NET 4.8).
  • Collaborate with front-end developers, QA team, and product managers to find a solution to reach functional and non-functional requirements.
  • Implement data security and protection measures.
  • Stay updated with emerging back-end technologies and best practices.
  • Troubleshoot, debug, and resolve issues in production and development environments.


Required Skills, Knowledge & Qualifications:

  • 5 years+ experience with .NET Core with API development for business oriented projects
  • High level of knowledge of EF
  • CQRS/MediatR experience in a workplace setting
  • Deep understanding of Clean Architecture
  • Familiarity with Modern C# patterns and approaches (primary constructors, records, nullable reference types, source generators, etc.)
  • Experience with Unit tests creation and modification (NSubstitute library)
  • AI tools knowledge and practical application skills
  • Located in Canada & legally entitled to work in Canada


Rentsync is an equal opportunity employer. If you are selected to participate in the interview process and require unique accommodations, please don’t hesitate to let us know. 

Successful candidates may be required to complete a criminal background check in the final phase of the interview process.

About this role

Summary

Develop and optimize server-side applications, APIs, and refactor legacy systems.

Job title

.NET Developer

Experience level

5+ years

Minimum experience

5+ years exp

Industry

software

Location requirements

Toronto or Westmount, Canada; remote work allowed

Salary

Not specified

Management role

No

Skills & keywords

Required skills

.NET CoreAPI developmentEFCQRSMediatRClean ArchitectureC# patternsunit testingNSubstituteAI tools

Preferred skills

None specified

Specializations

API developmentC# patternsClean ArchitectureEFAI tools
Locations

Structured locations inferred from the posting.

Toronto, ON, Canada

On-site City

Westmount, QC, Canada

On-site City

Canada

Remote Country