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.USTAR·File Extension

USTAR Data & Text — A .ustar file is a USTAR Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

Data & Textapplication/x-ustar

Quick facts

Extension.ustar

File typeUSTAR Data & Text

MIME typeapplication/x-ustar

CategoryData & Text

Charset—

Compressible—

What is .ustar

What is a .ustar file?

A .ustar file is a USTAR Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

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

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

How to open .ustar files

Use VS Code or Notepad++ to open and edit .ustar 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: application/x-ustar

Common software that reads/writes .ustar:

VS CodeNotepad++Sublime Textjq

Relation chain

.ustarextension of

format

USTAR Data & Textserved as

mime type

application/x-ustarsent via header

http header

Related extensions

Related MIME types

Common uses

Configuration files
Data interchange between systems
API request and response payloads
Logs and data exports

How to edit .ustar 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 .ustar files

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

Frequently asked questions

What programs can open .ustar files?

Common options include VS Code, Notepad++, Sublime Text. You can also open many of these files with built-in viewers or a browser.

How do I create a .ustar file?

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

What is the relationship between .ustar and the application/x-ustar MIME type?

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

Sources & standards

Updated 2026-09-13

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