.PKL File Extension
Apple Pkl File
| Developer | Apple |
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A PKL file contains code written in Pkl (pronounced “Pickle”), an embedded configuration language developed by Apple. It stores structured data, such as build settings, environment variables, and other metadata, used by Apple development tools like Xcode. PKL files typically contain plain text, but may also store binary data, and are often generated automatically during internal build processes or system-level configurations.
More Information
Apple introduced the Pkl configuration language in February 2024 and released it as an open-source project under the Apache 2.0 license. It is designed to simplify and standardize configuration management across Apple’s development tools. Pkl allows developers to define structured data in a clean and readable format and can export that data to formats like .JSON, .YAML, and Property Lists.
Developers may encounter PKL files when building or debugging macOS or iOS apps, especially while working with Xcode. They may find PKL files in the DerivedData directory, which stores temporary build results and cached information. Developers might inspect them when troubleshooting build issues, exploring how project settings are interpreted, or analyzing internal configuration behavior.
NOTE: Although PKL files use the same .pkl extension as Python pickle files, the two formats are unrelated and not compatible.
How to open a PKL file
PKL are not meant to be opened or edited manually. However, you can open PKL files that store plain text with a source code or text editor, such as Microsoft Notepad, Apple TextEdit, and Microsoft Visual Studio Code.
You can also parse or validate a PKL file with Apple’s open-source Pkl tool by first installing the command-line tool and running commands (e.g., pkl eval [filename].pkl).