Senior .NET Developer

Role Summary

As our Senior .NET Developer you’ll architect and ship cloud-native APIs on .NET 8+ and Azure, set the engineering standard across the team, and lead how we put AI development tools to work on real code every single day. This is a seat for an engineer who thinks like a product owner rather than a ticket-taker, and who wants to raise the bar for everyone around them.

This is a hybrid position, candidates are required to report in-office to one of Rentsync's regional offices 2 days per week on average.

Responsibilities

• Take full technical ownership of server-side logic and database structures — develop, maintain, and optimize them for performance and reliability.
• Take a product-oriented approach to development: understand product goals and user needs, and propose solutions that deliver real business value.
• Design and implement RESTful APIs and other web services to support front-end functionality, based on descriptions from the product team.
• Drive architecture decisions and uphold Clean Architecture, CQRS, and engineering standards across the team.
• Lead the adoption and day-to-day use of AI development tools on real projects, and mentor the team in using them effectively.
• Create and support Kubernetes configuration, deploy and run containerized services, and monitor their health and performance.
• Collaborate with front-end developers, the QA team, and product managers to meet functional and non-functional requirements.
• Implement data security and protection measures, including the safe handling of PII and other sensitive data.
• Mentor mid-level and junior developers and raise the technical bar through code reviews and knowledge sharing.
• Troubleshoot, debug, and resolve issues in production and development environments.
• Stay current with emerging back-end technologies and best practices.

Requirements

Essential Knowledge, Skills & Abilities

• Modern .NET engineering fundamentals: Clean Architecture, CQRS / MediatR, and Domain-Driven Design.
• Microsoft Azure platform: Compute Services, Azure SQL Database, Service Bus, Storage, Entra ID, Key Vault, and Application Insights.
• Kubernetes (K8s) concepts and configuration (manifests / Helm) and the operation of containerized services.
• SQL Server internals: schema and index design, execution-plan analysis, transactions, and concurrency.
• Secure handling of PII and other sensitive data.
• Expert-level Entity Framework Core: advanced querying, performance tuning, and migrations.
• Modern C# patterns (C# 12+): primary constructors, records, nullable reference types, and source generators.
• Advanced T-SQL and query tuning.
• Authoring and supporting Kubernetes manifests and Helm; deploying and operating containerized services; monitoring health, logs, and resource usage.
• Deploying to the cloud via DevOps pipelines.
• Daily, fluent use of AI development tools (e.g., GitHub Copilot, Claude Code, Cursor).
• Security-focused code review — spotting code and data-handling problems during reviews.
• Review, verify, and safely ship AI-generated code — and raise the whole team’s effectiveness with these tools.
• Design and operate cloud-native solutions.
• Take full technical ownership of design, delivery, and quality.
• Mentor developers, lead code review, and set and uphold engineering standards.
• Translate product goals and user needs into technical solutions — and proactively propose better ones.
• Troubleshoot, debug, and resolve issues across production and development environments.
• 8+ years of professional experience with modern .NET / .NET Core, building APIs for business-oriented projects.
• 2+ years carrying full technical ownership of design, delivery, and quality.
• Located in and legally entitled to work in Canada
• Able to work in one of Rentsync's regional offices (Toronto, Montreal or St. Catharines) 2-3 days per week on average

Additional Preferred Qualifications

• 2+ years of professional experience mentoring or leading junior developers
• Hands-on experience integrating LLMs into .NET.
• 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.
• This is an open-ended job posting and may not represent a specific vacancy within the organization.
• Rentsync reserves the right to use Artificial Intelligence to screen and/or assess candidates.

About the Company

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.