Senior Backend Developer (.NET)
Posted
Summary
Senior backend engineer driving the migration of a US tax software company's legacy system to a .NET 8+ Clean Architecture backend: building secure Web APIs, tuning MySQL access with Dapper/EF Core, and integrating payment providers (Braintree, Paymentech). Fully remote contractor role, hired through Niuro, paid in USD.
Compensation: $30k – $36k • No equity
A US tax software company is moving a critical legacy system to a modern .NET 8+ backend built on Clean Architecture, and needs a senior backend engineer to drive the API migration. The environment is high-availability, with complex business rules and strict security requirements.
What you'll do
- Translate complex legacy business logic into .NET 8+ Web APIs (Domain, Application, Infrastructure).
- Build secure APIs with strict authentication flows and compliance-driven session timeouts.
- Tune MySQL data access: Dapper for performance-critical paths, EF Core for the rest of the domain.
- Define API contracts with the Next.js frontend team and integrate payment providers (Braintree, Paymentech).
What we're looking for
- 5+ years of backend development with .NET / C# on enterprise services.
- Production experience with Clean Architecture and CQRS (MediatR or similar).
- Strong MySQL, with Dapper for complex queries and EF Core for domain work.
- Hands-on AWS: Fargate and RDS.
- Unit and integration testing as part of how you work.
- C1 English.
- Nice to have: payment gateways, regulated environments (SOC 2, PCI-DSS, GDPR), Redis, SQS or RabbitMQ.
Good to know
- Full-time, fully remote, contractor engagement, paid in USD (USD 2,500-3,000/month).
- Hiring through Niuro.
- Apply: https://app.niuro.io/source/dxEQSZTd?ref=ps_ibBPZs9Awr3aydkKBM-7GAPCrdIYQM7lfN8rogddxIo&utm_source=wellfound&utm_medium=job-board&utm_campaign=senior-backend-developer-net&utm_content=wellfound-20261026