Senior .NET Modernization Lead

First 60-90 days:
Take ownership of the codebase. Ship the final internal-launch scope on the legacy stack. Establish observability and deployment discipline in the existing environment.
Migration sequencing:
Design and lead the project-by-project modernization plan. Preserve DB-per-tenant model and PHI field-level encryption at every step.
Runtime & framework porting: Lead the port from .NET Framework 4.5-4.6 to .NET 8/9. Move ASP.
NET MVC 5 / Web API 2 to ASP.
NET Core. Migrate EF6 code-first to EF Core with multi-context patterns and per-tenant schema management. Refactor Autofac 3 to Microsoft.
Extensions.
DependencyInjection. Migrate ASP.
NET Identity 2 / OWIN to ASP.
NET Core Identity + OIDC / OAuth 2.0.
AWS re-platform:
Design and execute the move from Azure to AWS. Replace Azure Blob with S3, Azure Service Bus / Queues with SQS/SNS/EventBridge, Azure Redis with ElastiCache, Azure WebJobs with Lambda / ECS + EventBridge Scheduler, Application Insights + log4net with CloudWatch / OpenTelemetry / Serilog. Move to ECS/Fargate or EKS on containerized .NET. Move database from Azure SQL to RDS or Aurora using AWS DMS.
Security & key management:
Own PHI field-level encryption using AWS KMS. Move secrets to AWS Secrets Manager. Establish VPC design, IAM policies, least-privilege access appropriate to HIPAA-regulated SaaS.
CI/CD & IaC:
Move builds from MSBuild / Visual Studio to dotnet CLI + automated pipelines. Establish infrastructure-as-code (Terraform or AWS CDK). Raise test coverage using xUnit / NUnit + Moq.
Team leadership:
Manage two engineers directly — sprint planning, code review, mentorship. Coordinate architecture decisions with the Laravel Lead on shared services.
Compliance stewardship:
Maintain and extend HIPAA technical safeguards through the migration. Add GDPR compliance layer for future EU rollout. Add i18n infrastructure for multi-language rollout.
Yêu cầu:
8+ years of professional C# / .NET development
Both modern .NET (.NET 6/7/8/9) AND legacy .NET Framework 4.x production experience
Proven .NET Framework → .NET Core/8/9 migration experience at scale on a real production codebase
Deep hands-on experience migrating ASP.
NET MVC 5 / Web API 2 to ASP.
NET Core
Deep hands-on Entity Framework 6 → EF Core migration experience, including multi-context and code-first migration patterns
Modern C# fluency — nullable reference types, async/await throughout, pattern matching, records, primary constructors
Autofac → Microsoft.
Extensions.
DependencyInjection refactoring experience
ASP.
NET Core Identity + OIDC/OAuth 2.0 — migrated from ASP.
NET Identity 2/OWIN in production
HIPAA production implementation experience — field-level encryption, audit logging, access controls
Multi-tenant SaaS architecture experience — ideally DB-per-tenant, with tenant resolution middleware, per-tenant schema management, rolling schema changes
Hands-on AWS production experience: ECS/Fargate or EKS, RDS, VPC, IAM, Secrets Manager, KMS, S3, SQS/SNS/EventBridge, ElastiCache, CloudWatch
Strong SQL Server production experience, including performance tuning and rolling schema changes
Prior team lead experience — managed 2-4 engineers
Excellent English communication, verbal and written
Nice to Have
Prior experience with a full Azure-to-AWS re-platforming — the perfect-fit signal
AWS DMS experience for SQL Server migrations
Docker/Kubernetes for containerized .NET
Infrastructure-as-code experience (Terraform preferred, AWS CDK/CloudFormation acceptable)
SonarQube or similar static analysis tooling
Serilog + OpenTelemetry observability stack
Prior work on healthcare, wellness, med spa, or medical practice management software
SOC 2 audit preparation experience
GDPR compliance implementation experience
Front-end modernization experience (jQuery/Bootstrap → React)
Quyền lợi:
Salary:
USD 4,000-5,600/month gross, paid monthly via Multiplier Technologies Vietnam (Employer of Record)
13th-month bonus (1 month of salary, customary in Vietnam, paid every December)
Annual salary review with merit-based increases
Full Vietnamese statutory benefits administered via EOR: social insurance, health insurance, unemployment insurance, occupational accident and disease insurance
12+ days annual paid leave per Vietnamese Labor Code, plus all Vietnamese public holidays, plus sick and personal leave per Vietnamese Labor Code
Company-owned computer for your work
Access to our team space at Dreamplex, District 1 or District 3, Ho Chi Minh City
Company-provided VPN, MDM, security stack, and productivity software licenses
Direct mentorship from the US-based founder
Direct employment transition to Clearstone Software Vietnam Co., Ltd. planned for late 2026 / early 2027, with continuity of service preserved
Working Arrangement
Hybrid: 2-3 days per week at our HCMC team space (District 1 or 3), remainder home-based
Core overlap hours: 9:00 AM - 1:00 PM ICT for standup and synchronous work
Output-based culture — we value what you ship, not hours-in-chair
Initial 60-day probation via EOR, then indefinite-term contract
Application Process
Your CV (PDF)
Link to your GitHub profile or technical portfolio
Short cover note (3 paragraphs max): why you're interested, a specific .NET Framework → .NET Core migration you've led (sequencing, what nearly derailed it, what you'd do differently), and your point of view on preserving multi-tenant isolation and PHI encryption through a coordinated migration
Earliest start date and current salary expectation in USD/month
Process timeline: ~4 weeks from application to offer given the specialist nature of the role.