Dynamic Link Library — Windows shared library of executable code.
Quick facts
What is .dll
A .dll file is a Dynamic Link Library — Windows shared library of executable code.
In the mime-db registry it maps to application/octet-stream, and it is marked as compressible. When serving .dll over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to application/octet-stream — and is delivered over HTTP via the Content-Type header.
How to open .dll files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: application/octet-stream
Common software that reads/writes .dll:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .dll files
How to create .dll files
Frequently asked questions
Common options include Windows, Dependency Walker. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .dll extension.
application/octet-stream is the media type identifier used for .dll files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
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