What breaks in production — and what developers use instead

It usually starts with a simple requirement.

"Upload an Excel file, process it on the server, and export a report."

So you reach for Microsoft.Office.Interop.Excel . It's familiar. It's part of the Microsoft ecosystem. And it works — at least on your machine.

You open a workbook. You read a few cells. You write a test. Everything passes.

Then you deploy to production.

Within days, you start noticing things:

Excel processes quietly pile up in Task Manager, never exiting

Some requests hang indefinitely with no error, no timeout, no explanation

IIS recycles unexpectedly under moderate load

A background job that worked fine in staging fails intermittently

Deploying to a new server means installing Microsoft Office — and hoping the license key is somewhere

None of these failures are dramatic at first. They're subtle. They show up gradually.…