Senior .NET Engineer | Legacy Systems & Reverse Engineering (Onsite)

What is to be done

• Decompile the .NET binaries and read the code (ILSpy, dotPeek or similar).
• Review any remaining Classic ASP pages and ASPX sources on the server.
• Map the database: schemas, stored procedures, SSIS packages, SQL Agent jobs, replication.
• Reconstruct the business logic of each module: data collection, data services, reporting, archiving, user management.
• Document every integration from the application side, including aviation feeds such as Type B messages and ACARS.
• Interview users, the administrator, finance, and the teams using the other endpoints of each interface.
• Write the FSD, Integration Register and Data Dictionary.
• Work read-only on production. Report progress daily.

The three months

Period

Focus

Hand over

Month 1

Obtain access. Decompile the binaries, map the database, build a first picture of the application.

Application inventory, decompiled code baseline

Month 2

Work through the system module by module. Interview users, the admin, finance and the teams using each interface.

FSD drafts, integration register v1

Month 3

Complete and validate everything. Hand over the final documents and brief the decision gate.

Final FSD, Integration Register, Data Dictionary

Requirements

Must have

• 7+ years of .NET, with real depth in the Framework era — C# and VB.NET, ASP.NET WebForms.
• Hands-on reverse-engineering experience: decompiled and understood production systems with no source and no documentation.
• Strong SQL Server: T-SQL, stored procedures, SSIS, SQL Agent, replication.
• Integration experience: APIs, SFTP, file exchange and direct database links.
• Strong technical writing — we will ask to see examples of created documents.
• Fluent English and availability to work on-site in Cairo full-time.

Nice to have

• Airline systems background: Type B messages, ACARS, SSIM, Amadeus, Lido, AMOS or SAP.
• Arabic.
• Classic ASP, SSRS or Crystal Reports.
• Previous legacy modernisation or migration work.

Who fits

• Comfortable working in ambiguity — nothing is written down and there is no one to ask.
• Patient with people, precise with facts.
• Careful and discreet: sensitive data, read-only discipline, no risky moves on production.
• Honest daily and weekly reporting — no surprises at the monthly reviews.