Comparison with other available tools

Feature FlatImage Docker AppImage
No superuser privileges to use x x2 x
Overlayfs (allows to install programs even after compression) x
No installation necessary (click and use) x Requires docker on the host x
Requires building on an old system to minimize glibc issues N/A x
Mountable as a filesystem x x x3
Runs without mounting the filesystem x
Straightforward build process x x
Desktop integration x x
Extract the contents x x x
Supports reconfiguration without rebuild x x (layers)
No host libraries used (Filesystem Isolation) x x
Supports compression of specific directories/files in the package x
Portable mutable user configuration x x
Granular control over containerization x x
Works without fuse installed (still requires kernel support) x4 x x5
Layered filesystem x (overlayfs) x
Advanced networking management x
Advanced security features x
  1. Requires superuser privileges
  2. Only if the user is part of the docker group
  3. Only as read-only, you can mount FIM as read-write, before compression.
  4. Works without libfuse/libfuse3, still requires fusermount to be available.
  5. Experimental implementations, available here and here