Warning: This document is for an old version of Rasa. The latest version is 1.10.8.


The Domain defines the universe in which your assistant operates. It specifies the intents, entities, slots, and actions your bot should know about. Optionally, it can also include templates for the things your bot can say.

An example of a Domain

As an example, the DefaultDomain has the following yaml definition:

  - greet
  - goodbye
  - affirm
  - deny
  - mood_great
  - mood_unhappy
  - bot_challenge

- utter_greet
- utter_cheer_up
- utter_did_that_help
- utter_happy
- utter_goodbye
- utter_iamabot

  - text: "Hey! How are you?"

  - text: "Here is something to cheer you up:"
    image: "https://i.imgur.com/nGF1K8f.jpg"

  - text: "Did that help you?"

  - text: "Great, carry on!"

  - text: "Bye"

  - text: "I am a bot, powered by Rasa."

What does this mean?

Your NLU model will define the intents and entities that you need to include in the domain.

Slots hold information you want to keep track of during a conversation. A categorical slot called risk_level would be defined like this:

      type: categorical
      - low
      - medium
      - high

Here you can find the full list of slot types defined by Rasa Core, along with syntax for including them in your domain file.

Actions are the things your bot can actually do. For example, an action could:

  • respond to a user,

  • make an external API call,

  • query a database, or

  • just about anything!

Custom Actions and Slots

To reference slots in your domain, you need to reference them by their module path. To reference custom actions, use their name. For example, if you have a module called my_actions containing a class MyAwesomeAction, and module my_slots containing MyAwesomeSlot, you would add these lines to the domain file:

  - my_custom_action

  - my_slots.MyAwesomeSlot

The name function of MyAwesomeAction needs to return my_custom_action in this example (for more details, see Custom Actions).

Utterance templates

Utterance templates are messages the bot will send back to the user. There are two ways to use these templates:

  1. If the name of the template starts with utter_, the utterance can directly be used as an action. You would add the utterance template to the domain:

      - text: "Hey! How are you?"

    Afterwards, you can use the template as an action in the stories:

    ## greet the user
    * intent_greet
      - utter_greet

    When utter_greet is run as an action, it will send the message from the template back to the user.

  2. You can use the templates to generate response messages from your custom actions using the dispatcher: dispatcher.utter_message(template="utter_greet"). This allows you to separate the logic of generating the messages from the actual copy. In you custom action code, you can send a message based on the template like this:

    from rasa_sdk.actions import Action
    class ActionGreet(Action):
      def name(self):
          return 'action_greet'
      def run(self, dispatcher, tracker, domain):
          return []

Images and Buttons

Templates defined in a domain’s yaml file can contain images and buttons as well:

  - text: "Hey! How are you?"
    - title: "great"
      payload: "great"
    - title: "super sad"
      payload: "super sad"
  - text: "Here is something to cheer you up:"
    image: "https://i.imgur.com/nGF1K8f.jpg"


Please keep in mind that it is up to the implementation of the output channel on how to display the defined buttons. The command line, for example, can’t display buttons or images, but tries to mimic them by printing the options.

Custom Output Payloads

You can also send any arbitrary output to the output channel using the custom: key. Note that since the domain is in yaml format, the json payload should first be converted to yaml format.

For example, although date pickers are not a defined parameter in utterance templates because they are not supported by most channels, a Slack date picker can be sent like so:

  - custom:
      - type: section
          text: "Make a bet on when the world will end:"
          type: mrkdwn
          type: datepicker
          initial_date: '2019-05-21'
            type: plain_text
            text: Select a date

Channel-Specific Utterances

If you have certain utterances that you would like sent only to specific channels, you can specify this with the channel: key. The value should match the name defined in the name() method of the channel’s OutputChannel class. Channel-specific utterances are especially useful if creating custom output payloads that will only work in certain channels.

  - text: "Which game would you like to play?"
    channel: "slack"
      - # payload for Slack dropdown menu to choose a game
  - text: "Which game would you like to play?"
    - title: "Chess"
      payload: '/inform{"game": "chess"}'
    - title: "Checkers"
      payload: '/inform{"game": "checkers"}'
    - title: "Fortnite"
      payload: '/inform{"game": "fortnite"}'

Each time your bot looks for utterances, it will first check to see if there are any channel-specific templates for the connected channel. If there are, it will choose only from these utterances. If no channel-specific templates are found, it will choose from any utterances that do not have a defined channel. Therefore, it is good practice to always have at least one template for each utterance that has no channel specified so that your bot can respond in all environments, including in the shell and in interactive learning.


You can also use variables in your templates to insert information collected during the dialogue. You can either do that in your custom python code or by using the automatic slot filling mechanism. For example, if you have a template like this:

  - text: "Hey, {name}. How are you?"

Rasa will automatically fill that variable with a value found in a slot called name.

In custom code, you can retrieve a template by using:

class ActionCustom(Action):
   def name(self):
      return "action_custom"

   def run(self, dispatcher, tracker, domain):
      # send utter default template to user
      # ... other code
      return []

If the template contains variables denoted with {my_variable} you can supply values for the fields by passing them as keyword arguments to utter_message:

dispatcher.utter_message(template="utter_greet", my_variable="my text")


If you want to randomly vary the response sent to the user, you can list multiple responses and Rasa will randomly pick one of them, e.g.:

  - text: "Hey, {name}. How are you?"
  - text: "Hey, {name}. How is your day going?"

Ignoring entities for certain intents

If you want all entities to be ignored for certain intents, you can add the use_entities: [] parameter to the intent in your domain file like this:

  - greet:
      use_entities: []

To ignore some entities or explicitly take only certain entities into account you can use this syntax:

- greet:
      - name
      - first_name
      - location
      - age

This means that excluded entities for those intents will be unfeaturized and therefore will not impact the next action predictions. This is useful when you have an intent where you don’t care about the entities being picked up. If you list your intents as normal without this parameter, the entities will be featurized as normal.


If you really want these entities not to influence action prediction we suggest you make the slots with the same name of type unfeaturized.