Senior .NET Full-Stack Engineer

Mission Telecom is a 501(c)(4) nonprofit wireless broadband provider and grantmaking foundation. We partner with nonprofits, schools, and libraries to close the digital divide through reliable, affordable wireless broadband and connected devices, and through Mission Telecom Giving, we fund social impact organizations working to advance equity and justice. Our grantmaking focuses on multiracial democracy, movement infrastructure and innovation, and telecom justice, including broadband affordability policy.

About the Role

Mission Telecom is seeking a Senior .NET Full-Stack Engineer to develop and support software systems, integrations, and automations across the organization. A central focus is Mission Connect, our custom business application supporting sales, customer management, billing, payments, fulfillment, and operational workflows. Mission Connect is nearing its initial production launch with an established architecture, automated testing and deployment controls, and defined engineering standards. After launch, this position will assume primary engineering ownership of the platform.

This is a broad, hands-on role spanning full-stack development, integrations, PostgreSQL, security, Azure operations, and production support. The role reports to the CTO, who remains actively involved in architecture, priorities, release planning, and technical escalation, and works directly with leadership and business stakeholders to turn operational needs into reliable software.

Key Responsibilities

Application Development and Business Automation

Design, develop, test, maintain , and support Mission Telecom software applications using C#, .NET 10, ASP.NET Core, Blazor Server, Radzen , and related technologies.

Build staff and customer-facing interfaces, application services, business logic, background processing, and data-access functionality.

Serve as the primary hands-on engineer for software systems, partnering with the CTO and business stakeholders on priorities, technical decisions, and release planning.

Own the technical design and implementation of assigned application features and enhancements within Mission Telecom's established technology direction.

Translate business processes and operational requirements into automated workflows supporting grantmaking, marketing, lead management, sales, billing, payments, fulfillment, customer service, reporting, and other organizational functions.

Deliver maintainable, incremental enhancements to existing applications and workflows.

Develop scripts, utilities, and automation for data exchange, system administration, diagnostics, deployment, integration support, and operational tasks.

Own assigned work from requirements and technical design through development, testing, deployment, and support.

APIs and System Integrations

Design, build, maintain , and troubleshoot secure integrations between internal and third-party systems.

Develop and consume REST APIs, webhooks, SDKs, file-based exchanges, and other system-to-system integration methods.

Support integrations across CRM, marketing, lead generation, advertising, analytics, accounting, payments, communications, and telecom platforms, including systems such as HubSpot, Salesforce, Apollo.io, RB2B, Google, Meta, NetSuite, payment processors, and service providers.

Implement reliable patterns for authentication, synchronization, error handling, retries, rate limits, duplicate prevention, and reconciliation.

Diagnose and resolve integration issues across applications, data, authentication, and third-party platforms.

Design integrations that can adapt as Mission Telecom's business systems and processes evolve.

Databases and Financial Systems

Design, maintain , troubleshoot, and optimize PostgreSQL and other databases supporting Mission Telecom.

Work with relational data models, tables, relationships, primary and foreign keys, constraints, indexes, SQL queries, Entity Framework Core, and application data access.

Diagnose database performance, concurrency, and data-integrity issues.

Plan and execute controlled database schema changes using established migration, validation, and deployment practices.

Develop and support financial and operational workflows involving orders, invoices, payments, taxes, adjustments, refunds, provisioning, and customer accounts.

Build and maintain NetSuite and payment processor integrations with appropriate transaction integrity, auditability, and reconciliation.

Maintain appropriate customer data isolation and financial correctness across billing, tax, payment, and reconciliation workflows.

Security and Identity

Develop and maintain authentication, authorization, and role-based access controls.

Configure and support Microsoft Entra ID capabilities used by applications, including app registrations, enterprise applications, permissions, managed identities, secrets, and certificates.

Work with OAuth 2.0, OpenID Connect, and related identity standards.

Apply secure development practices to customer information, financial data, APIs, file handling, application access, and cloud resources.

Azure Operations and Software Quality

Deploy, monitor, troubleshoot, and support applications and services within Microsoft Azure.

Work with Azure App Service, PostgreSQL, Key Vault, Application Insights, managed identities, networking, configuration, logging, and related services.

Build and maintain CI/CD processes using GitHub and GitHub Actions or comparable tooling.

Own application monitoring, incident investigation, recovery procedures, and root-cause resolution, with the CTO providing technical backup and escalation support.

Develop and maintain unit, integration, and end-to-end automated testing for business-critical workflows.

Use Playwright or comparable tools to validate important staff and customer workflows.

Perform code reviews and maintain appropriate technical documentation for applications, integrations, configuration, and support procedures.

AI-Assisted Engineering

Use AI-assisted development tools and coding agents to improve productivity across analysis, development, testing, troubleshooting, documentation, and code review.

Work within a structured AI-assisted development process that uses scoped tasks, review checkpoints, independent validation, and documented review before release.

Evaluate AI-generated code for correctness, security, performance, and maintainability.

Independently understand the codebase, design solutions, write and modify production code, and troubleshoot issues without reliance on generated output.

Use AI tools within approved security and data-handling requirements and independently verify generated work before release.

What Success Looks Like

Mission Connect stable and supported in production, with engineering ownership fully transitioned from leadership

Business requests delivered as working enhancements and automations on a consistent release schedule

Reliable integrations, with errors caught and resolved quickly

Accurate, auditable billing, payment, and reconciliation workflows

Production issues resolved at the root cause, with decreasing reliance on CTO escalation over time

Current automated test coverage and documentation for business-critical workflows

What You'll Need

7 or more years of professional software development experience, or equivalent demonstrated experience building and supporting complex production business applications.

Advanced proficiency with C#, .NET, ASP.NET Core, and modern full-stack web application development.

Proven ability to design, build, and support REST APIs and integrations with third-party business systems.

Proficiency with SQL, relational database design, data modeling, indexes, keys, query optimization, and database troubleshooting.

Experience building and supporting business-critical transactional or operational applications where