Sr. Software Developer – Application Migration & Modernization ( 102-08SENG-01)
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.
Requirements
What you will do
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Assess existing .NET Framework applications — dependencies, integration points, data access patterns — and produce a realistic modernization plan with sequencing and risk called out.
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Modify the application codebase itself to support PostgreSQL as the backend, beyond just migrating the underlying data.
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Untangle and port data access layers, including legacy ADO.NET and older Entity Framework code, to current patterns.
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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.
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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.
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Work directly with client architects, DBAs, and product owners; explain trade-offs in plain language and document decisions so the next person understands them.
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Contribute to CI/CD pipelines, deployment automation, and observability for the systems you migrate.
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Mentor mid-level developers and review code with an eye on maintainability, not just correctness.
Required
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10+ years of professional software development experience, with significant depth in C# and .NET.
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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.
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Demonstrated experience modernizing or migrating existing applications — not just greenfield development.
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Solid relational database skills: writing and tuning SQL, reading execution plans, understanding transaction and isolation behaviour.
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Hands-on Oracle experience — PL/SQL, packages, procedures, triggers, sequences — enough to read and reason about business logic living in the database.
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Experience with source control, branching strategy, and CI/CD in a team setting (Git, Azure DevOps, GitHub Actions, or similar).
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Ability to communicate clearly with non-engineers and to work well when requirements are incomplete.
Engagement details
- 100% emote
- Hourly, full-time commitment
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2-month engagement with the possibility of extension
- Open to candidates in Latin America
Highlights
Tech stack
C#, .NET Framework 4.8, ASP.NET MVC, Web API, Web Forms, WCF, IIS, Windows Services, Oracle PL/SQL, PostgreSQL, PL/pgSQL, SQL, Git, CI/CD (Azure DevOps / GitHub Actions), AWS (EC2, RDS)
Originally posted on Himalayas