Firejail is a security sandbox tool designed to enhance the security of applications by isolating them in a sandbox environment. It is a free and open-source software available for Linux-based operating systems. Firejail was created by Antti Kantee and is maintained by a community of developers.

Firejail is typically used to run potentially untrusted applications or scripts in a controlled environment. It can be invoked directly from the command line or configured to run specific applications automatically.