Senior Software Engineer (.NET/Multi-Tenant SaaS)
B5 Recruiting•Minneapolis, MN
•Remote
About The Position
Join a project team on a contract basis to build a modern multi-tenant web platform that enables business customers to manage their data and workflows. The solution includes a React or Next.js front end, a .NET Core API, and single sign-on for customer organizations. Work alongside the project architect to design and build the platform, set code quality standards, and mentor junior and mid-level engineers. Take ownership of application security and tenant data isolation to ensure each customer can access only its own data. The role also involves contributing to delivery planning, CI/CD, observability, technical documentation, and knowledge transfer to the client's development team.
Requirements
- At least 6 years of professional software engineering experience, including significant experience building production APIs in .NET Core (C#).
- Strong understanding of RESTful API design, including versioning, error handling, pagination, and API documentation with OpenAPI/Swagger.
- Experience with relational databases, preferably SQL Server, including data modeling, query tuning, and Entity Framework Core.
- Working knowledge of OAuth 2.0 and OpenID Connect, including token-based authentication, scopes, claims, and role- and policy-based authorization.
- Solid understanding of multi-tenancy, including tenant isolation strategies, tenant resolution, and per-tenant configuration.
- Demonstrated ability to build secure applications and protect customer data against common web vulnerabilities.
- Experience writing automated unit and integration tests and working with source control, code review, and CI/CD.
- Experience mentoring or technically guiding other engineers.
- Ability to become productive quickly in an unfamiliar codebase and work independently in a remote setting.
- Strong written and verbal communication skills and comfort collaborating with architects, designers, project managers, and client stakeholders across distributed teams.
Nice To Haves
- Located in or near Grand Rapids, Michigan.
- Experience with React or Next.js, including TypeScript, component-based design, and state management.
- Experience with SCIM or automated user provisioning and role mapping from identity-provider groups.
- Prior work on multi-tenant SaaS products, including per-tenant branding or configuration.
- Familiarity with Azure services, Azure DevOps or other CI/CD tooling, and applications hosted on Windows Server/IIS.
- Experience with audit logging, observability (logging, monitoring, correlation IDs), and performance profiling.
- Experience designing and building APIs for partner or third-party integrations.
- Experience replacing or modernizing legacy systems.
- Prior consulting or contract engagements involving joining a team mid-stream and handing work off to a client team.
- Experience working in an Agile/Scrum environment.
Responsibilities
- Partner with the architect to design and build the multi-tenant application, including its API, data model, and tenant-aware application logic.
- Design and develop secure, documented RESTful APIs in .NET Core for the web application and external integrations.
- Implement authentication and authorization using OAuth 2.0 and OpenID Connect, including SSO integrations with customer identity providers.
- Enforce tenant data isolation across the API, data layer, and application, and verify it through testing and code review.
- Build and review React or Next.js front-end features for customer data management.
- Review code and establish standards for quality, maintainability, performance, and testing; ensure delivered work meets requirements and acceptance criteria.
- Mentor junior and mid-level engineers through pairing, code review, and guidance on design decisions.
- Apply secure development practices, including OWASP guidance, input validation, least-privilege access, and secrets management; help identify and fix vulnerabilities.
- Contribute to estimation, backlog refinement, and sprint planning; communicate progress, risks, and trade-offs to the team and client.
- Help establish and maintain CI/CD pipelines, logging, monitoring, and technical documentation.
- Document key design decisions and support knowledge transfer to the client's development team.
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What This Job Offers
Career Level
Senior
Education Level
No Education Listed
