What is MIME type "text/x-protobuf"?

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

The MIME type text/x-protobuf is assigned to files that define data structures for Protocol Buffers.
It uses a text format that developers read and edit directly. This file defines the schema for structured data that is later serialized in binary form for efficient processing.
Developers write these definitions in files usually saved with the PROTO extension. They then use it to generate source code for tasks like data exchange between services.

Main Use: Describe message structures for communication and storage.
Guidelines: Provide a blueprint that helps in creating auto-generated code across different programming languages.
Benefits: Enable efficient, compact binary data serialization while keeping the schema human-readable.

For deeper details on Protocol Buffers, visit the official documentation.

Associated file extensions

.proto

Usage Examples

HTTP Header

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


    Content-Type: text/x-protobuf

HTML

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


    <a href="file.dat" type="text/x-protobuf">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', 'text/x-protobuf');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.proto

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.