In addition to the [built-in variables](/templates/variables/) available from Hugo, you can specify your own custom data that can be accessed via templates or shortcodes.
Hugo supports loading data from [YAML](http://yaml.org/), [JSON](http://www.json.org/), and [TOML](https://github.com/toml-lang/toml) files located in the `data` directory.
**It even works with [LiveReload](/extras/livereload/).**
Data Files can also be used in [themes](/themes/overview/), but note: If the same `key` is used in both the main data folder and in the theme's data folder, the main one will win. So, for theme authors, for theme specific data items that shouldn't be overridden, it can be wise to prefix the folder structure with a namespace, e.g. `mytheme/data/mytheme/somekey/...`. To check if any such duplicate exists, run hugo with the `-v` flag, e.g. `hugo -v`.
As explained in [Source Organization](/overview/source-directory/), the `data` folder is where you can store additional data for Hugo to use when generating your site. These files must be YAML, JSON or TOML files (using either the `.yml`, `.yaml`, `.json` or `toml` extension) and the data will be accessible as a `map` in `.Site.Data`.
[Jaco Pastorius](http://en.wikipedia.org/wiki/Jaco_Pastorius_discography) was a great bass player, but his solo discography is short enough to use as an example. [John Patitucci](http://en.wikipedia.org/wiki/John_Patitucci) is another bass giant.
The example below is a bit constructed, but it illustrates the flexibility of Data Files. It uses TOML as file format.
The list of bass players can be accessed via `.Site.Data.jazz.bass`, a single bass player by adding the filename without the suffix, e.g. `.Site.Data.jazz.bass.jacopastorius`.
