| Adobe Acrobat Plugin Format | |
| Adobe Systems | |
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API files are used as web browser plugins. API file format allows PDF to be displayed directly in web browsers. API plugins are created using Netscape Plug-In API (NPAPI).
Windows
Mac OS
| .aaui | Adobe Acrobat UI Settings Format |
| .accda | Microsoft Access 2007/2010 Add-in Format |
| .accdu | Microsoft Access 2007/2010 Database Wizard Format |
| .acroplugin | Adobe Acrobat Plug-in Format |
| .addon | CFS Console Add-on Format |
| .aip | Adobe Illustrator Plugin Format |
| .alp | Ableton Live Pack Format |
| .amxx | AMX Mod X Plug-in Format |