API, Adobe Photoshop Inks File (.api)
The API Settings file format
Adobe Photoshop uses a special file format for saving settings in a file. These settings files are typically saved using the API extension. The API files enable users of the image editing program Photoshop to save their color settings to match the print or scanning options on several printers and scanners across devices. Other associations with the API extensions come from Adobe Acrobat plug-ins.
Technical details of API files
API files are binary files that save settings information of the Adobe Photoshop program. The files contain settings about the ink colors used to print images manipulated and edited in Photoshop.