What is an XLL file?
A .XLL file is a Microsoft Excel Add-in file created by Microsoft. It provides custom functions, data tools, and new menus for Microsoft Excel. Under the hood, a .XLL file is a compiled binary file. It operates much like a standard DLL or EXE file, but it is built specifically to integrate with spreadsheet software.
How to open XLL files?
You normally open a .XLL file using Microsoft Excel. You can add it to the program through the Add-ins manager. Because a .XLL file contains compiled executable code, it requires a compatible Windows operating system to run. You must be careful when opening unknown add-ins, as they can execute harmful code on your computer.
Inspect files online
viewer.online/xll analyzes .XLL files to identify their exact format and creator software. It shows which programs can open the file and usually previews its internal metadata and structural data. If you have an unknown add-in, viewer.online/xll will help you safely identify the actual format of the user's file without running the code.
Summary
Because .XLL files use the known EXE format, viewer.online/xll can safely open and display them online. This eliminates compatibility problems and allows you to inspect the add-in securely from your web browser.