Senior Full-Stack .NET API Developer

Salary: $85,000 - 125,000 per year Requirements:

• We require at least 5 years of professional software development experience.
• We look for strong experience with C#.
• We require strong experience with .NET and ASP.NET Core.
• We require strong REST API development experience.
• We require strong SQL Server experience.
• We expect experience building production web applications.
• We look for experience with JavaScript and/or TypeScript.
• We expect experience with React or another modern JavaScript framework.
• We require experience using Git.
• We need strong debugging and problem-solving skills.
• We expect the ability to work in an existing production codebase rather than only greenfield projects.
• We strongly prefer experience with .NET 6/7/8 or later.
• We strongly prefer experience with Entity Framework Core.
• We strongly prefer experience with Swagger/OpenAPI.
• We strongly prefer experience with Azure and Azure DevOps.
• We strongly prefer experience with Playwright and automated API testing.
• We strongly prefer experience with Microsoft Graph.
• We strongly prefer experience with OAuth/OIDC authentication.
• We strongly prefer experience with enterprise applications.
• We strongly prefer experience with large SQL Server databases.
• We prefer hands-on experience with AI development tools such as Claude Code, OpenAI Codex, GitHub, Cursor, or similar agentic coding environments.
• We expect candidates to explain how they use AI to improve productivity without reducing software quality.

• We design, build, maintain, and enhance RESTful APIs using C# and .NET.
• We create API endpoints for CRUD operations and more complex business workflows.
• We define and uphold consistent API standards for routing, methods, status codes, validation, error handling, authorization, filtering, and sorting.
• We maintain API documentation.
• We analyze API performance and implement improvements.
• We integrate our APIs with existing email management functionality.
• We develop and optimize SQL queries.
• We write and maintain stored procedures when needed.
• We review execution plans and resolve database performance issues.
• We design indexes and improve database performance.
• We preserve data integrity and transactional consistency.
• We work through concurrency challenges, including optimistic and pessimistic updates.
• We handle large document-management datasets.
• We maintain and improve the existing React application.
• We build new screens and components.
• We connect React components to REST APIs.
• We troubleshoot UI and API integration issues.
• We work with state management, asynchronous calls, and error handling.
• We follow existing UI components and design standards.
• We contribute to functionality around users, email/document profiles and metadata, search, folder structures, permissions, versioning, relationships, full-text search, Microsoft 365 integrations, and Microsoft Graph.
• We use AI tools to speed up understanding of existing code, code generation, refactoring, test creation, debugging, SQL optimization, code reviews, Playwright tests, legacy code analysis, and production issue investigation.
• We review AI-generated code for correctness, security, performance, maintainability, architectural consistency, SQL/data integrity, and regression risk.
• We help establish and expand automated testing, including unit, API, integration, SQL/database, React component, end-to-end browser, Playwright, and regression testing.
• We participate in Git source control, code reviews, CI/CD, Azure DevOps, and issue tracking.

• AI
• API
• ASP.NET
• Azure
• C#
• CI/CD
• Claude Code
• Cursor
• DevOps
• Git
• GitHub
• Support
• JavaScript
• Microsoft 365
• OAuth
• Office 365
• OpenAPI
• Playwright
• REST
• React
• SQL
• Security
• Swagger
• TypeScript
• Web
• UX UI Design
• Cloud
• Fullstack

More:

We develop and support enterprise software used by office professionals to manage email, calendars, clients, contacts, and related Office 365 information. Our browser-based Office Software uses a modern React front end, C#/.NET REST APIs, and a Microsoft SQL Server database. This full-time, in-person role offers the chance to work on a mature enterprise application while helping modernize our architecture and development process. We are looking for experienced software developers who can become important members of our development team and help transform how our product is built through modern AI-assisted development.

last updated 34 week of 2026