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.CDX·File Extension

CDX Other — A .cdx file is a CDX Other. It is a file format typically read and written by specialized applications.

Otherchemical/x-cdx

Quick facts

Extension.cdx
File typeCDX Other
MIME typechemical/x-cdx
CategoryOther
Charset—
Compressible—

What is .cdx

What is a .cdx file?

A .cdx file is a CDX Other. It is a file format typically read and written by specialized applications.

In the mime-db registry it maps to chemical/x-cdx. When serving .cdx over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to chemical/x-cdx — and is delivered over HTTP via the Content-Type header.

How to open .cdx files

  • Use VS Code or xxd to open and edit .cdx files.
  • Any text editor (Notepad, VS Code) can inspect the raw content as text.

Developer info

When served over HTTP, responses should set the following header:

Content-Type: chemical/x-cdx

Common software that reads/writes .cdx:

VS Codexxd7-Zip

Relation chain

.cdxextension of
format
CDX Otherserved as
mime type
chemical/x-cdxsent via header
http header
Content-Type

Related extensions

.cif
CIF Other
.cmdf
CMDF Other
.cml
CML Other
.csml
CSML Other

Related MIME types

chemical/x-cdx
.cdx

Common uses

  • Application-specific data

How to edit .cdx files

  • Open the file with VS Code, make your changes and save.
  • Most editors preserve the original formatting and encoding — avoid changing the charset.

How to create .cdx files

  • Create a new file and save it with the .cdx extension, or export this format from VS Code.

Frequently asked questions

What programs can open .cdx files?

Common options include VS Code, xxd, 7-Zip. You can also open many of these files with built-in viewers or a browser.

How do I create a .cdx file?

Create a new file in any text editor or the app that owns the format and save it with the .cdx extension.

What is the relationship between .cdx and the chemical/x-cdx MIME type?

chemical/x-cdx is the media type identifier used for .cdx files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-09-13

Explore this reference

Related extensions

.cif
CIF Other
.cmdf
CMDF Other
.cml
CML Other
.csml
CSML Other

Related MIME types

chemical/x-cdx
.cdx

Related headers

Content-Type
HTTP header
Accept
HTTP header

Related methods

GET
HTTP method
POST
HTTP method
PUT
HTTP method
PATCH
HTTP method

Related status codes

200
OK
404
Not Found

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