What is MIME type "application/x-coffexec"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

application/x-coffexec identifies files in the Common Object File Format (COFF).
It marks binary files that hold compiled machine code and symbol information. These files are typically generated during the compilation process and wait to be linked into a full executable.

Intermediate Object Code – They contain code segments and data used for linking.
Debug Support – They store symbols that help in troubleshooting and performance tuning.
Build Processes – They are a standard output from compilers and assemblers in various development environments.

Files using this MIME type often use extensions like OBJ and O.
For more technical details, see the COFF article on Wikipedia.

Associated file extensions

.obj, .o

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-coffexec

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-coffexec">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/x-coffexec');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.obj, .o

FAQs

What is the purpose of the application/x-coffexec MIME type?

This MIME type identifies files in the Common Object File Format (COFF), which contain compiled machine code and debugging data. These are typically intermediate object files created during software compilation that must be linked to form a final executable.

Which file extensions commonly use application/x-coffexec?

This type is most frequently associated with .obj files on Windows systems and .o files on Unix/Linux systems. You can learn more about these extensions at OBJ or O.

Can I run or execute a file with this MIME type directly?

No, files served as application/x-coffexec are not standalone executables. They are partial binaries that require a linker to combine them with other object files and libraries to create a runnable program (such as an .exe or ELF binary).

How do I configure Apache to serve .obj files with this MIME type?

To ensure your Apache server sends the correct header, add the following line to your .htaccess file or main configuration: AddType application/x-coffexec .obj .o. This helps client applications identify the binary format correctly.

Why does my browser try to download these files instead of displaying them?

Browsers cannot render binary object code natively. Because application/x-coffexec indicates a binary format meant for software development tools, browsers will default to downloading the file for local processing.

Is application/x-coffexec a standard IANA MIME type?

The x- prefix indicates that this is a non-standard or experimental subtype. While widely recognized in specific development environments, generic binary files are often served as application/octet-stream if a specific handler is not configured.

How can I view the contents of an application/x-coffexec file?

You cannot read these files with a text editor. Developers use command-line tools like dumpbin (Microsoft Visual Studio), objdump, or nm (GNU Binutils) to inspect the symbol tables and assembly code within the file.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.