Senior Platform Software Engineer – Backend

DSI Recruiting; Toronto; On-site; CAD 120,000 - 160,000; Full time

Job summary

DSI Recruiting supports a client seeking a hands-on Senior Platform Software Engineer (Backend) to build shared cloud-native services and reusable .NET SDKs for a next-generation enterprise platform. The role emphasizes security, API standards, session management, and tenant-aware authorization across domain services, delivering production-grade components and AI-assisted development practices.

Contribute to Azure DevOps pipelines and adopt secure, scalable backend patterns in a fast-paced

Qualifications

• 5+ years of backend engineering experience.
• Strong C#, .NET, ASP.NET Core and secure REST API development.
• Solid knowledge of OAuth 2.0 and OIDC.
• Experience with SQL/relational databases and asynchronous programming.
• Experience with AWS or comparable cloud platforms.
• Ability to contribute to architecture and implement production‑grade components independently.

Skills

C#

ASP.NET Core

OAuth 2.0

SQL Databases

AWS Cloud

CI/CD

Backend Architecture

Security Best Practices

Job description

Our client is seeking a hands‑on Senior Platform Software Engineer (Backend) to implement shared cloud‑native services and reusable .NET SDKs for a next‑generation enterprise application platform. The role focuses on security, API standards, session management, resilient integrations and developer enablement across independently delivered domain services.

Build shared services, middleware, templates and reusable NuGet SDKs using C#, modern .NET and ASP.NET Core.

Implement authentication integration, BFF session management, token lifecycle controls and tenant‑aware, resource‑level authorization patterns.

Establish API standards for validation, versioning, structured errors, idempotency, configuration and service‑toservice integration.

Develop reusable patterns for PostgreSQL access, Redis caching/session storage, observability and resilient messaging as appropriate.

Contribute to AWS‑based deployments, including API Gateway, ECS/Fargate, Aurora/RDS PostgreSQL, ElastiCache, SQS and EventBridge where relevant.

Publish packages through Azure DevOps Artifacts and support domain teams in adoption without unnecessary coupling.

AI‑assisted development and quality

• Use Claude Code or comparable AI coding assistants for design exploration, implementation, refactoring, testing and documentation.
• Apply structured, specification‑driven AI‑assisted delivery approaches, including AWS AI‑DLC 2.0; turn requirements into reviewable plans and acceptance criteria.
• Review and verify AI‑generated code for security, correctness, maintainability and compliance with platform standards.
• Contribute to Azure DevOps CI/CD pipelines, automated tests, peer reviews and engineering quality gates.

Required qualifications

• Typically 5+ years of professional backend engineering experience, or equivalent demonstrated capability.
• Strong C#, modern .NET, ASP.NET Core and secure REST API development experience.
• Solid knowledge of OAuth 2.0, OIDC, application security, authentication and authorization.
• Experience with SQL/relational databases, transactions, asynchronous programming and failure‑resistant service design.
• Experience with AWS or comparable cloud platforms, automated testing, Git and CI/CD.
• Ability to contribute to architecture and implement production‑grade components independently.

Preferred qualifications

• AWS ECS/Fargate, API Gateway, Aurora PostgreSQL, ElastiCache, SQS, EventBridge, Secrets Manager and CloudWatch.
• BFF patterns, enterprise federation (Entra ID/PingFederate), Redis, multitenant authorization and OpenTelemetry.
• Transactional outbox/inbox, event versioning, duplicate‑message handling, Flyway, Terraform and Azure DevOps Artifacts.
• Demonstrable hands‑on use of Claude Code, GitHub Copilot or similar AI tools; familiarity with AWS AI‑DLC 2.0.
• Production‑ready shared backend components and versioned .NET SDKs.
• Reference services, secure authentication/session and authorization integration patterns.
• Automated tests, pipeline integration, operational instrumentation and adoption documentation.