Working with files

There are many different ways to create and/or access files. The file paths and the ways your access these files varies depending on the type of file and the location of the file.

Functions for file and folder access

Defold provides several different functions to work with files:

  • You can use the standard io.* functions to read and write files. These functions give you very fine-grained control over the entire I/O process.
  • You can use os.rename() and os.remove() to rename and remove files.
  • You can use and sys.load() to read and write Lua tables. Additional sys.* functions exist to help with platform independent file path resolution.

File and folder locations

File and folder locations can be divided into three categories:

  • Application specific files created by your application
  • Files and folders bundled with your application
  • System specific files accessed by your application

How to save and load application specific files

When saving and loading application specific files such as high scores, user settings and game state it is recommended to do so in a location provided by the operating system and intended specifically for this purpose. You can use sys.get_save_file() to get the OS specific absolute path to a file. Once you have the absolute path you can use the sys.*, io.* and os.* functions (see above).

Check the example showing how to use and sys.load().

How to access files bundled with the application

You can bundle files with your application in two ways:

  1. As part of the game archive using the Custom Resources field in game.project. You can read these files using sys.load_resource(). Note that these aren’t actual files on the file system. Files included this way becomes part of the binary game archive and the only way to access them is through sys.load_resource().

  2. As additional files and folders located as a part of your application bundle using the Bundle Resources field in game.project. You can use sys.get_application_path() to get the path to where the application is stored. Use this application base path to create the final absolute path to the files you need access to. Once you have the absolute path of these files you can use the io.* and os.* functions to access the files (see above).

System file access

Access to system files may be restricted by the operating system for security reasons. You can use the extension-directiories native extension to get the absolute path to some common system directories (ie documents, resource, temp). Once you have the absolute path of these files you can use the io.* and os.* functions to access the files (see above).


The Asset Portal contains several assets to simplify file and folder access. Some examples:

  • Lua File System (LFS) - Functions to work with directories, file permissions etc
  • DefSave - A module to help you save / load config and player data between session.

Did you spot an error or do you have a suggestion? Please let us know on GitHub!