Frequently Asked Questions

Any plans to use Python 3?

Older releases of QL use Python 2. As of release 4.0.0, QL is Python 3 only.

Why don’t you use SQLite for the song database?

Although the song data Quod Libet stores would benefit from a relational database, it does not have a predefined schema, and opts to let users define their own storage keys. This means relational databases based on SQL, which require predefined schemata, cannot be used directly.

What about <my favourite NoSQL DB> then?

This gets asked fairly often. MongoDB, CouchDB etc are indeed a closer match to the existing setup, but there is significant work porting to any of these, and each comes with a compatibility / maintenance cost. There has to be a genuine case for the benefits outweighing the migration cost.

Any environment variables I should know about?


When set to a string will enclose all translatable strings with that string. This is useful for testing how the layout of the user interface behaves with longer text as can occur with translations and to see if all visible text is correctly marked as translatable.

When in the environment gives the same result as if --debug was passed.

Can be set to the audio backend, overriding the value present in the main config file. Useful for quickly testing a different audio backend.


Can be set to a (potentially not existing) directory which will be used as the main config directory. Useful to test Quod Libet with a fresh config, test the initial user experience, or to try out things without them affecting your main library.