If you are decompiling proprietary software, you may be violating the Terms of Service or copyright laws. Only decompile files you own or those that fall under fair use/educational purposes.
Online decompilers are great for small scripts or quick checks, but they have limits on file size and processing power. If you are serious about reverse engineering, you should eventually download industry-standard (and free) desktop tools: exe decompiler online free link
If your EXE was built using the .NET framework (common for Windows apps), tools like ILSpy or dotPeek are the gold standard. While usually desktop apps, some web-based sandboxes allow you to upload assemblies for quick inspection. How Online Decompilers Work Most online decompilers follow a three-step process: Upload: You send your .exe file to their server. If you are decompiling proprietary software, you may
This is arguably the most popular "all-in-one" online decompiler. It supports a wide range of file types, including .NET, Java, and Android binaries. Simply upload your EXE, and it will attempt to reconstruct the source tree. If you are serious about reverse engineering, you
Originally a project by Avast, RetDec is a powerful tool for analyzing machine code. While the web interface has changed hands over the years, searching for "RetDec online" often leads to community-hosted versions that can deconstruct x86 and ARM executables.
Developed by the NSA, this is a world-class, open-source reverse engineering suite. ILSpy: The go-to for anything .NET. x64dbg: For real-time debugging of Windows executables.