What Is a .war File? .war Format, MIME & How to Open

Quick facts

Extension.war

File typeWeb Application Archive

MIME typeapplication/java-archive

CategoryArchive

Charset—

CompressibleNo

Format familyjava

What is .war

What is a .war file?

A .war file is a Web Application Archive — Java web application archive for servlet containers.

In the mime-db registry it maps to application/java-archive, and it is marked as non-compressible. When serving .war over HTTP, set the Content-Type header as shown in Developer info below.

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

How to open .war files

Use Tomcat or 7-Zip to open and edit .war 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/java-archive

Common software that reads/writes .war:

Tomcat7-Zip

Relation chain

.warextension of

format

javaserved as

mime type

application/java-archivesent via header

http header

Related extensions

Related MIME types

application/java-archive

.jar .war .ear

Common uses

File distribution
Backup bundles
Software installation packages

How to edit .war files

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

How to create .war files

Create a new file and save it with the .war extension, or export this format from Tomcat.

Frequently asked questions

What programs can open .war files?

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

How do I create a .war file?

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

What is the relationship between .war and the application/java-archive MIME type?

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

Sources & standards

Updated 2026-09-13

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