This role modernizes legacy .NET applications and their data tiers onto supportable platforms. Most engagements start with a working-but-aging system — a .NET Framework 4.8 application backed by Oracle — and end with something maintainable, scalable, and testable on PostgreSQL RDS with Windows application servers on EC2. This is hands-on engineering with real constraints: production systems that can't go down, undocumented application logic, business logic buried in stored procedures nobody has read in a decade, and a migration that needs to be seamless and invisible to end users.
Critically, this is not a database-only migration: the application layer itself must be modified to support PostgreSQL as the backend, not just have its data moved underneath it.
What you will do
- Assess existing .NET Framework applications — dependencies, integration points, data access patterns — and produce a realistic modernization plan with sequencing and risk called out.
- Modify the application codebase itself to support PostgreSQL as the backend, beyond just migrating the underlying data.
- Untangle and port data access layers, including legacy ADO.NET and older Entity Framework code, to current patterns.
- Migrate database workloads from Oracle to PostgreSQL: schema conversion, PL/SQL to PL/pgSQL translation, data type and collation mismatches, query rewrites, and performance validation on the target.
- Write the tests that make a migration defensible: characterization tests around legacy behaviour, integration tests across the data tier, and automated comparison of old vs. new outputs.
- Work directly with client architects, DBAs, and product owners; explain trade-offs in plain language and document decisions so the next person understands them.
- Contribute to CI/CD pipelines, deployment automation, and observability for the systems you migrate.
- Mentor mid-level developers and review code with an eye on maintainability, not just correctness.
- Required 10+ years of professional software development experience, with significant depth in C# and .NET.
- Strong, current working knowledge of .NET Framework 4.8 and its legacy stack — ASP.NET MVC/Web API, Web Forms, WCF, IIS, and Windows Services.
- Demonstrated experience modernizing or migrating existing applications — not just greenfield development.
- Solid relational database
skills:
- writing and tuning SQL, reading execution plans, understanding transaction and isolation behaviour.
- Hands-on Oracle experience — PL/SQL, packages, procedures, triggers, sequences — enough to read and reason about business logic living in the database.
- Experience with source control, branching strategy, and CI/CD in a team setting (Git, Azure DevOps, GitHub Actions, or similar).
- Ability to communicate clearly with non-engineers and to work well when requirements are incomplete.
- Engagement details 100% emote Hourly, full-time commitment 2-month engagement with the possibility of extension Open to candidates in Latin America
