Data Files

In addition to the built-in variables available from Jekyll, you can specify your own custom data that can be accessed via the Liquid templating system.

Jekyll supports loading data from YAML, JSON, and CSV files located in the _data directory. Note that CSV files must contain a header row.

This powerful feature allows you to avoid repetition in your templates and to set site specific options without changing _config.yml.

Plugins/themes can also leverage Data Files to set configuration variables.

The Data Folder

As explained on the directory structure page, the _data folder is where you can store additional data for Jekyll to use when generating your site. These files must be YAML, JSON, or CSV files (using either the .yml, .yaml, .json or .csv extension), and they will be accessible via site.data.

Example: List of members

Here is a basic example of using Data Files to avoid copy-pasting large chunks of code in your Jekyll templates:

In _data/members.yml:

- name: Eric Mill
  github: konklone

- name: Parker Moore
  github: parkr

- name: Liu Fengyun
  github: liufengyun

Or _data/members.csv:

name,github
Eric Mill,konklone
Parker Moore,parkr
Liu Fengyun,liufengyun

This data can be accessed via site.data.members (notice that the filename determines the variable name).

You can now render the list of members in a template:

<ul>
{% for member in site.data.members %}
  <li>
    <a href="https://github.com/{{ member.github }}">
      {{ member.name }}
    </a>
  </li>
{% endfor %}
</ul>

If your Jekyll site has a lot of pages, such as with documentation websites, see the detailed examples in how to build robust navigation for your site.

Example: Organizations

Data files can also be placed in sub-folders of the _data folder. Each folder level will be added to a variable’s namespace. The example below shows how GitHub organizations could be defined separately in a file under the orgs folder:

In _data/orgs/jekyll.yml:

username: jekyll
name: Jekyll
members:
  - name: Tom Preston-Werner
    github: mojombo

  - name: Parker Moore
    github: parkr

In _data/orgs/doeorg.yml:

username: doeorg
name: Doe Org
members:
  - name: John Doe
    github: jdoe

The organizations can then be accessed via site.data.orgs, followed by the file name:

<ul>
{% for org_hash in site.data.orgs %}
{% assign org = org_hash[1] %}
  <li>
    <a href="https://github.com/{{ org.username }}">
      {{ org.name }}
    </a>
    ({{ org.members | size }} members)
  </li>
{% endfor %}
</ul>

Example: Accessing a specific author

Pages and posts can also access a specific data item. The example below shows how to access a specific item:

_data/people.yml:

dave:
    name: David Smith
    twitter: DavidSilvaSmith

The author can then be specified as a page variable in a post’s frontmatter:

---
title: sample post
author: dave
---

{% assign author = site.data.people[page.author] %}
<a rel="author"
  href="https://twitter.com/{{ author.twitter }}"
  title="{{ author.name }}">
    {{ author.name }}
</a>

For information on how to build robust navigation for your site (especially if you have a documentation website or another type of Jekyll site with a lot of pages to organize), see Navigation.