Files with idx extension can be usually encountered as various index files from all kind of programs and applications.
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.IDX file extension - Index file
What is idx file? How to open idx files?
File type specification:
File extension idx is traditionally used for index files. Many programs use them, but no unified format exists. Nevertheless, they are generated for the very same purposes - to speed up file or database search. You may find these indexes mainly in database programs, but even some video subtitling programs or media players use them.
These files are usually generated by programs to speed up the searching through large number of files. In most cases if you delete this file, it will be recreated the next time the index process is started again.
Index files usually contain one header record and one or many node records. The header record contains information about the root node, the current file size, the length of the key, index options and signature, and printable ASCII representations of the key1 and FOR expressions. The header record starts at file position zero.
Note: There is no connection to Internet Data Exchange and this file type.
The default software associated to open idx file:
Visual FoxPro 
(obsolete software)
Company or developer:
Microsoft Corporation
Microsoft Visual FoxPro is set of tools that is used to create database applications, desktop applications and web applications. Visual FoxPro uses own proprietary data centric object oriented and procedural programming language. Visual FoxPro is available for Microsoft Windows.
List of software applications associated to the .idx file extension
Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open idx file, edit idx file, convert idx file, view idx file, play idx file etc. (if exist software for corresponding action in File-Extensions.org's database).
Hint:
Click on the tab below to simply browse between the application actions, to quickly get a list of recommended software, which is able to perform the specified software action, such as opening, editing or converting idx files.
Programs that can create idx file - Index file
Programs supporting the exension idx on the main platforms Windows, Mac, Linux or mobile. Click on the link to get more information about listed programs for create idx file action.
Microsoft Windows:
Main software associated with idx file by default:
Visual FoxPro (obsolete/discontinued)
Other suggested software:
Norton SystemWorks (obsolete/discontinued)
PocoMail
Aid4Mail
Pro/Engineer (Creo Elements/Pro) (obsolete/discontinued)
ArcGIS for Desktop Basic (ArcView)
Forte Agent
