Senior Full-Stack Software Engineer
Candidates must be legally authorized to work in the United States on a full-time basis; Mosaic is unable to sponsor or engage C2C for this role now or in the future. This position is open to candidates residing anywhere in the U.S. with occasional travel to client sites (up to 25%).
About the role
We are seeking a hands-on Senior Full-Stack Software Engineer to contribute to the architecture, design, and delivery of modern web applications. This role is ideal for a senior developer who enjoys solving complex technical problems, building across the stack, and partnering with product, design, data science, and engineering teams to deliver secure, scalable, cloud-native software.
You will work across the full stack—from Svelte frontend applications to .NET/C# backend services, APIs, SQL databases, and Azure infrastructure—while shaping implementation approaches, supporting engineering standards, mentoring teammates, and making thoughtful technical decisions that balance speed, quality, and maintainability. Depth in React, .NET/C#, and SQL is valued more than equal expertise across every technology in the stack.
Responsibilities
- Design, build, and deliver full-stack applications using React, .NET/C#, SQL, and Azure
- Contribute hands-on to daily development across frontend, backend, APIs, and data layers
- Guide technical design, implementation approach, and engineering best practices
- Review code, mentor junior engineers, and support overall code quality and maintainability
- Design and optimize APIs, services, data models, and relational databases in SQL Server and PostgreSQL
- Improve CI/CD pipelines and support Azure deployment, monitoring, and production operations
- Partner with product, design, data science, and client stakeholders to turn requirements into effective technical solutions
- Contribute to technical planning, documentation, troubleshooting, and continuous improvement across projects
Requirements
- 8+ years of professional experience building and delivering full-stack software in production environments
- Strong hands-on experience with Svelte, .NET/C#, and SQL, including relational database design and performance optimization in SQL Server and PostgreSQL
- Experience building and deploying applications on Azure
- Proven experience designing and building RESTful APIs, authentication and authorization flows, and secure cloud-based systems
- Strong system design skills and the ability to contribute to architecture and technical direction
- Experience delivering software in enterprise, consulting, or other complex production environments
- Familiarity with Python and comfort working in a multi-language environment
- Familiarity with AI-enabled application features or AI-assisted development workflows
- Strong written and verbal communication skills, with the ability to work effectively across technical and non-technical teams
- Demonstrated ability to mentor other engineers, review code, and deliver high-quality work on schedule
Preferred Qualifications
- Experience with Docker, Kubernetes, microservices, and event-driven architectures
- Familiarity with AI/ML integrations, data pipelines, or intelligent application features
- Experience improving deployment processes, observability, and operational resilience
- Strong understanding of accessibility standards, usability principles, and modern UI/UX patterns
Qualifications
Bachelor’s degree in Computer Science or a related field, or equivalent practical experience.
Pay
A reasonable national base salary range for this position is $115,000.00 – $175,000.00 USD annually. Compensation decisions are dependent on relevant skills, experience, education, geographic location, and other business needs.
This position is eligible to participate in a bonus program of up to 10% of annual compensation, subject to individual and organizational performance.
Benefits
- Comprehensive health and wellness benefits
- Flexible Time Off program
- Paid holidays
- Discretionary 401(k) match
- Employee Stock Ownership Plan (ESOP) for U.S.-based employees