Smart Reply

With ML Kit's Smart Reply API, you can automatically generate relevant replies to messages. Smart Reply helps your users respond to messages quickly, and makes it easier to reply to messages on devices with limited input capabilities.

iOS Android

Key capabilities

Generates contextually-relevant suggestions The Smart Reply model generates reply suggestions based on the full context of a conversation, and not just a single message, resulting in suggestions that are more helpful to your users.
Runs on the device The on-device model generates replies quickly, and doesn't require you to send users' messages to a remote server.


  • Smart Reply is intended for casual conversations in consumer apps. Reply suggestions might not be appropriate for other contexts or audiences.
  • Currently, only English is supported. The model automatically detects if a different language is used and if so, will not provide suggestions.

How the model works

  • The model uses up to 10 of the most recent messages from a conversation history to generate reply suggestions.
  • It detects the language of the conversation and only attempts to provide responses when the language is determined to be English.
  • Next, the model compares the messages against a list of sensitive topics and won’t provide suggestions when it detects a sensitive topic.
  • If the language is determined to be English and no sensitive topics are detected, the model provides up to three suggested responses. The number of responses depends on how many meet a sufficient level of confidence based on the input to the model.

Providing feedback

Due to the complexity of natural language processing, the suggestions provided by the model might not be appropriate for all contexts or audiences. If you encounter inappropriate reply suggestions, reach out to Firebase support. Your feedback helps to continue to improve the model and sensitive topic filter.

Example results


Timestamp User ID Local User? Message
Thu Feb 21 13:13:39 PST 2019 true are you on your way?
Thu Feb 21 13:15:03 PST 2019 FRIEND0 false Running late, sorry!

Suggested replies

Suggestion #1 Suggestion #2 Suggestion #3
No worries 😞 No problem!