developers.home-assistant/docs/documentation_standards.md

title
Standards

To ensure that the documentation for Home Assistant is consistent and easy to follow for both novice and expert users, we ask that you follow a very strict set of standards for developing the documentation.

General Documentation

• The language of the documentation should be American-English.
• Don't put two spaces after a period and avoid the "Oxford comma".
• There is no limit for the line length. You are allowed to write in a flowing text style. This will make it easier to use the GitHub online editor in the future.
• Be objective and not gender favoring, polarizing, race related or religion inconsiderate.
• The case of brand names, services, protocols, components and platforms must match its respective counterpart. e.g., "Z-Wave" not "Zwave", "Z-wave", "Z Wave" or "ZWave". Also, "Input Select" not "input select" or "Input select".
• All headings should use the {% linkable_title %} tag.
• Do not use ALL CAPITALS for emphasis - use italics instead.

Component and Platform Pages

• The Configuration Variables section must use the {% configuration %} tag.
• Configuration variables must document the requirement status (false or true).
• Configuration variables must document the default value, if any.
• Configuration variables must document the accepted value types (see Configuration variables details).
  • For configuration variables that accept multiple types, separate the types with a comma (i.e. string, int).
• Use YAML sequence syntax in the sample code if it is supported.
• All examples should be formatted to be included in configuration.yaml unless explicitly stated.
  • Use capital letters and _ to indicate that the value needs to be replaced. E.g., api_key: YOUR_API_KEY or api_key: REPLACE_ME.
  • If you know that the API key or value contains control characters, e.g., #, [, ?, etc., wrap it in quotes and add a note.
• Component and platform names should be a link to their respective documentation pages.

Example configuration block

{% configuration %}
some_key:
  description: This is a description of what this key is for.
  required: false
  type: string
  default: Optional default value - leave out if there isn't one
{% endconfiguration %}

Templates

• All examples containing Jinja2 templates should be wrapped outside of the code markdown with the {% raw %} tag.
• Do not use states.switch.source.state in templates. Instead use states() and is_state().
• Use double quotes (") for (more information):
  • friendly_name
  • Single-line templates:
    • value_template
    • level_template
    • icon_template
    • Children of data_template
• Use single quotes (') for (more information:
  • Strings inside of templates:
    • States
    • Entity IDs
  • unit_of_measurement
• No whitespace around pipe character (|) for Jinja2 filters.
• Single whitespace after Jinja2 opening delimiters ({% raw %}{{{% endraw %}).
• Single whitespace before Jinja2 closing delimiters ({% raw %}}}{% endraw %}).
• Do not quote values for:
  • device_class
  • platform
  • condition
  • service

Renaming Pages

It can happen that a component or platform is renamed, in this case the documentation needs to be updated as well. If you rename a page, add redirect_from: to the file header and let it point to the old location/name of the page. Please consider to add details, like release number or old component/platform name, to the page in a note.

---
...
redirect_from: /getting-started/android/
---

Adding a redirect also applies if you move content around in the documentation.

Single vs. Double Quotation Marks

Use single quotes (') for strings inside of a template. It is more obvious to escape a single quote when necessary (i.e. name is a possessive noun), because the single quotes that wrap the string are closer in position to the apostrophe inside the string. Use double quotes (") outside of a template (unless it is a multi-line template, in which case outside quotes are not required).

Examples

Double Quotes Outside, Single Quotes Inside (Valid)

automation:
  ...
  action:
    - service: notify.notify
      data_template:
        message: "{% if trigger.to_state.name == 'Dale\'s Bedroom' %}Someone's in your base, killing your noobs!{% else %}It's just another door.{% endif %}"

Single Quotes Outside, Double Quotes Inside (Invalid)

automation:
  ...
  action:
    - service: notify.notify
      data_template:
        message: '{% if trigger.to_state.name == "Dale's Bedroom" %}Someone's in your base, killing your noobs!{% else %}It's just another door.{% endif %}'

Multi-Line Template (Valid)

automation:
  ...
  action:
    - service: notify.notify
      data_template:
        message: >-
          {% if trigger.to_state.name == 'Dale\'s Bedroom' %}
            Someone's in your base, killing your noobs!
          {% else %}
            It's just another door.
          {% endif %}