Dogbolt is an open-source web frontend that allows you to run an unmanaged DLL or executable through multiple native decompilers simultaneously. Native (C/C++) DLL files.
A DLL decompiler is a tool that takes a compiled DLL file as input and generates a high-level representation of the code, making it possible to understand, modify, and even reverse-engineer the original code. This process is also known as decompilation or disassembly.
Online tools run inside a web browser. This means you can decompile a Windows DLL file even if you are currently working on a macOS, Linux, or ChromeOS machine.
For actual development work (restoring source code or fixing bugs), these desktop tools are the industry standard:
If you are dealing with native DLLs and want to look at the raw structural headers (PE headers), online hex editors and PE analyzers can break down the entry points, exported methods, and resource sections of the DLL. Step-by-Step: How to Decompile a DLL Online