What is File and Directory Entries API

Mon Mar 20 2023

3 min read

As web apps are becoming common, the need for accessing and manipulating files or directories on the user's device has become increasingly important. The File and Directory Entries API is a JavaScript API that enables web applications to do just that.

In this guide, we'll take a closer look at what the File and Directory Entries API is, how to use it, and some security considerations that you should keep in mind.

File and Directory Entries API

The File and Directory Entries API is a Web API that lets applications access the file system of the user's device. This API enables you to perform file and directory operations such as reading, writing, creating, deleting, and renaming files and directories.

The API makes use of a virtual file system that is separate from the physical file system of the device. This means that it requires the user’s permission to access or modify files outside of its virtual file system.

A physical file system is directly managed by an operating system and is responsible for organizing and storing files and directories on a device's storage media. In comparison, a virtual file system is an abstraction layer that sits on top of the physical file system and provides a standardized interface for applications to interact with the file system.


To use the File and Directory Entries API, a web application must first request permission from the user to access the file system. Once permission is granted, the app has access to the user’s files and directories.


The File and Directory Entries API provides a set of methods to interact with the user’s file system. Some of the methods include:

  • getFile(): returns a file object for a given file path
  • getDirectory(): returns a directory object for a given directory path
  • createReader(): used to read the contents of a directory. It returns a FileSystemDirectoryReader object.
  • remove(): deletes a file or directory from the file system
  • moveTo(): moves a file or directory to a new location in the file system


Since the API provides access to the user's file, it can potentially be used for malicious purposes, such as stealing sensitive information or deleting important files.

To ensure secure usage of the API, you should always:

  • Request permission from the user before accessing the file system
  • Use the API only for intended purposes and avoid unnecessary file access
  • Validate user input to prevent malicious file names or paths
  • Use encryption and other security measures to protect sensitive data

Wrap up

The File and Directory Entries API provides web developers with a powerful new tool for accessing and manipulating files and directories on the user's local filesystem. If you want to learn more about file systems, we have written another piece on a similar API.