.PAC File Extension
Proxy Auto-Config File
| Developer | Netscape |
| Popularity |
3.9 | 77 Votes |
What is a PAC file?
A PAC file is a configuration file used by web browsers to select an appropriate proxy server. It contains one or more JavaScript functions with one of them named FindProxyForURL, which defines rules for choosing a proxy server based on a given URL. PAC files are used for controlling and load-balancing Internet traffic, especially in corporate environments.
More Information
PAC files are enabled in web browsers by entering the PAC file URL in the proxy connection settings, or by using the Web Proxy Auto-Discovery (WPAD) protocol. When executed, a PAC file returns a string with one or more proxy server URLs. PAC files are typically hosted on a web server and are named proxy.pac.
Since PAC files contain the configuration in plain text. You can use a text editor, such as Microsoft Notepad or Apple TextEdit to view or modify the files.
NOTE: The PAC file format was originally released in 1996 for use by Netscape Navigator 2.0.
Programs that open PAC files
PAC Subtitles File
| Developer | Screen Subtitling Systems |
| Popularity |
3.9 | 24 Votes |
Programs that open PAC files
Hedgehog Engine 3D Model
| Developer | Sonic Team |
| Popularity |
4.2 | 6 Votes |
A PAC file may also be a 3D model used in a video game developed by SEGA or Sonic Team. Notably, the games Sonic Forces and Sonic Lost World use 3D models saved as PAC files.
More Information
PAC files are 3D models used in games that use the Sonic Team's Hedgehog Engine game engine. In addition to Sonic Forces and Sonic Lost World, Puyo Puyo Tetris 2, Sakura Wars, Mario & Sonic at the Olympic Games Tokyo 2020, Mario & Sonic at the Rio 2016 Olympic Games, and Olympic Games Tokyo 2020 - The Official Video Game use PAC files.
Most players who play these games will never encounter the games' PAC files. However, some enthusiastic modders have created tools that allow them to extract, edit, and create their own PAC files.
How to open a PAC file
You can use HedgeLib (cross-platform) to extract PAC files from a Hedgehog Engine game. Then, you can use Noesis (Windows) to open the files' contents and convert them to other 3D model formats.
After you've finished editing your PAC file, you can use HedgeLib to repackage the file and insert it into a Hedgehog Engine game.
Programs that open or reference PAC files
SBStudio II Song File
| Developer | SonicSpot |
| Popularity |
3.0 | 12 Votes |
Song format, called a PAC or package file, used by SBStudio; made up of data blocks that store song information and audio data.
Programs that open PAC files
STAD Graphic File
| Developer | STAD |
| Popularity |
2.7 | 14 Votes |
Image format used by the STAD program for Atari ST systems; saved as a black and white image with a resolution of 640x400 pixels; considered a high-resolution graphic for Atari computers.
Programs that open PAC files
WWE 2K Game Data Archive
| Developer | Yuke's |
| Popularity |
1.0 | 2 Votes |
A PAC file may also be an archive that contains game data used by a game in the WWE 2K series. For example, it may contain game audio, animations, textures, and/or character models. Modders have created tools that allow them to decompress and extract data from PAC files.
More Information
WWE 2K is a series of pro wrestling video games. Prior to WWE 2K20, games in the series were developed by Yuke's. These entries store various types of game data in PAC files.
Although PAC files are not meant to be opened by players, WWE 2K modders have developed tools that allow them to extract the data the files contain. Modders can also use these tools to add files to existing PAC files, to insert custom audio, animations, and characters into a game.
How to open a PAC file
You can use PAC Editor (Windows) or rePac (Windows) to view and extract the files a PAC file contains.