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ML Kit can generate short replies to messages using an on-device model.
To generate smart replies, you pass ML Kit a log of recent messages in a
conversation. If ML Kit determines the conversation is in English, and that
the conversation doesn't have potentially sensitive subject matter, ML Kit
generates up to three replies, which you can suggest to your user.
Model is statically linked to your app at build time.
Model is dynamically downloaded via Google Play Services.
App size impact
About 5.7 MB size increase.
About 200 KB size increase.
Initialization time
Model is available immediately.
Might have to wait for model to download before first use.
Try it out
Play around withthe sample appto
see an example usage of this API.
Before you begin
In your project-levelbuild.gradlefile, make sure to include Google's
Maven repository in both yourbuildscriptandallprojectssections.
Add the dependencies for the ML Kit Android libraries to your module's
app-level gradle file, which is usuallyapp/build.gradle. Choose one of
the following dependencies based on your needs:
To bundle the model with your app:
dependencies{// ...// Use this dependency to bundle the model with your appimplementation'com.google.mlkit:smart-reply:17.0.4'}
If you choose to use the model in Google Play Services, you can configure
your app to automatically download the model to the device after your app is
installed from the Play Store. By adding the following declaration to your
app'sAndroidManifest.xmlfile:
You can also explicitly check the model availability and request download through
Google Play servicesModuleInstallClient API.
If you don't enable install-time model downloads or request explicit download,
the model is downloaded the first time you run the smart reply generator.
Requests you make before the download has completed produce no results.
1. Create a conversation history object
To generate smart replies, you pass ML Kit a chronologically-orderedListofTextMessageobjects, with the earliest timestamp first.
Whenever the user sends a message, add the message and its timestamp to the
conversation history:
Kotlin
conversation.add(TextMessage.createForLocalUser("heading out now",System.currentTimeMillis()))
Java
conversation.add(TextMessage.createForLocalUser("heading out now",System.currentTimeMillis()));
Whenever the user receives a message, add the message, its timestamp, and the
sender's user ID to the conversation history. The user ID can be any string that
uniquely identifies the sender within the conversation. The user ID doesn't need
to correspond to any user data, and the user ID doesn't need to be consistent
between conversation or invocations of the smart reply generator.
Kotlin
conversation.add(TextMessage.createForRemoteUser("Are you coming back soon?",System.currentTimeMillis(),userId))
Java
conversation.add(TextMessage.createForRemoteUser("Are you coming back soon?",System.currentTimeMillis(),userId));
A conversation history object looks like the following example:
Timestamp
userID
isLocalUser
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!
ML Kit suggests replies to the last message in a conversation history. The last message
should be from a non-local user. In the example above, the last message in the conversation
is from the non-local user FRIEND0. When you use pass ML Kit this log, it suggests
replies to FRIENDO's message: "Running late, sorry!"
2. Get message replies
To generate smart replies to a message, get an instance ofSmartReplyGeneratorand pass the conversation history to itssuggestReplies()method:
Kotlin
valsmartReplyGenerator=SmartReply.getClient()smartReply.suggestReplies(conversation).addOnSuccessListener{result->if(result.getStatus()==SmartReplySuggestionResult.STATUS_NOT_SUPPORTED_LANGUAGE){// The conversation's language isn't supported, so// the result doesn't contain any suggestions.}elseif(result.getStatus()==SmartReplySuggestionResult.STATUS_SUCCESS){// Task completed successfully// ...}}.addOnFailureListener{// Task failed with an exception// ...}
Java
SmartReplyGeneratorsmartReply=SmartReply.getClient();smartReply.suggestReplies(conversation).addOnSuccessListener(newOnSuccessListener(){@OverridepublicvoidonSuccess(SmartReplySuggestionResultresult){if(result.getStatus()==SmartReplySuggestionResult.STATUS_NOT_SUPPORTED_LANGUAGE){// The conversation's language isn't supported, so// the result doesn't contain any suggestions.}elseif(result.getStatus()==SmartReplySuggestionResult.STATUS_SUCCESS){// Task completed successfully// ...}}}).addOnFailureListener(newOnFailureListener(){@OverridepublicvoidonFailure(@NonNullExceptione){// Task failed with an exception// ...}});
If the operation succeeds, aSmartReplySuggestionResultobject is passed to
the success handler. This object contains a list of up to three suggested replies,
which you can present to your user:
Note that ML Kit might not return results if the model isn't confident in
the relevance of the suggested replies, the input conversation isn't in
English, or if the model detects sensitive subject matter.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eML Kit's Smart Reply API generates up to three relevant reply suggestions for English conversations using an on-device model.\u003c/p\u003e\n"],["\u003cp\u003eYou can integrate Smart Reply by either bundling the model with your app (larger size) or dynamically downloading it (smaller size, requires Google Play Services).\u003c/p\u003e\n"],["\u003cp\u003eTo use the API, provide a conversation history as input, and ML Kit will suggest replies to the last message if it's from a non-local user.\u003c/p\u003e\n"],["\u003cp\u003eThe suggested replies are returned only if the conversation is in English, does not contain sensitive content, and the model is confident in their relevance.\u003c/p\u003e\n"]]],["ML Kit generates up to three smart replies to messages in English conversations, excluding sensitive content. This is done by passing a chronologically ordered list of `TextMessage` objects to the `suggestReplies()` method. The API can use a bundled model (5.7 MB increase) or an unbundled model (200 KB increase) via Google Play Services. The unbundled model may have a delay before the first use, and may not include any results. Implementation requires adding the appropriate library dependency and building the conversation history.\n"],null,["ML Kit can generate short replies to messages using an on-device model.\n\nTo generate smart replies, you pass ML Kit a log of recent messages in a\nconversation. If ML Kit determines the conversation is in English, and that\nthe conversation doesn't have potentially sensitive subject matter, ML Kit\ngenerates up to three replies, which you can suggest to your user.\n\n\u003cbr /\u003e\n\n| This API is available using either an unbundled library that must be downloaded before use or a bundled library that increases your app size. See [this guide](/ml-kit/tips/installation-paths) for more information on the differences between the two installation options.\n\n| | Bundled | Unbundled |\n|-------------------------|-------------------------------------------------------|------------------------------------------------------------|\n| **Library name** | `com.google.mlkit:smart-reply` | `com.google.android.gms:play-services-mlkit-smart-reply` |\n| **Implementation** | Model is statically linked to your app at build time. | Model is dynamically downloaded via Google Play Services. |\n| **App size impact** | About 5.7 MB size increase. | About 200 KB size increase. |\n| **Initialization time** | Model is available immediately. | Might have to wait for model to download before first use. |\n\n| **Note:** The unbundled version of Smart Reply is currently offered in beta, which means it might be changed in backward-incompatible ways and is not subject to any SLA or deprecation policy.\n\nTry it out\n\n- Play around with [the sample app](https://github.com/googlesamples/mlkit/tree/master/android/smartreply) to see an example usage of this API.\n\nBefore you begin This API requires Android API level 21 or above. Make sure that your app's build file uses a `minSdkVersion` value of 21 or higher.\n\n1. In your project-level `build.gradle` file, make sure to include Google's\n Maven repository in both your `buildscript` and `allprojects` sections.\n\n2. Add the dependencies for the ML Kit Android libraries to your module's\n app-level gradle file, which is usually `app/build.gradle`. Choose one of\n the following dependencies based on your needs:\n\n - To bundle the model with your app:\n\n dependencies {\n // ...\n // Use this dependency to bundle the model with your app\n implementation 'com.google.mlkit:smart-reply:17.0.4'\n }\n\n - To use the model in Google Play Services:\n\n dependencies {\n // ...\n // Use this dependency to use the dynamically downloaded model in Google Play Services\n implementation 'com.google.android.gms:play-services-mlkit-smart-reply:16.0.0-beta1'\n }\n\n If you choose to use the model in Google Play Services, you can configure\n your app to automatically download the model to the device after your app is\n installed from the Play Store. By adding the following declaration to your\n app's `AndroidManifest.xml` file: \n\n \u003capplication ...\u003e\n ...\n \u003cmeta-data\n android:name=\"com.google.mlkit.vision.DEPENDENCIES\"\n android:value=\"smart_reply\" \u003e\n \u003c!-- To use multiple models: android:value=\"smart_reply,model2,model3\" --\u003e\n \u003c/application\u003e\n\n You can also explicitly check the model availability and request download through\n Google Play services [ModuleInstallClient API](https://developers.google.com/android/guides/module-install-apis).\n\n If you don't enable install-time model downloads or request explicit download,\n the model is downloaded the first time you run the smart reply generator.\n Requests you make before the download has completed produce no results.\n\n\n 1. Create a conversation history object\n\n To generate smart replies, you pass ML Kit a chronologically-ordered `List`\n of `TextMessage` objects, with the earliest timestamp first.\n\n Whenever the user sends a message, add the message and its timestamp to the\n conversation history: \n\n Kotlin \n\n ```kotlin\n conversation.add(TextMessage.createForLocalUser(\n \"heading out now\", System.currentTimeMillis()))\n ```\n\n Java \n\n ```java\n conversation.add(TextMessage.createForLocalUser(\n \"heading out now\", System.currentTimeMillis()));\n ```\n\n Whenever the user receives a message, add the message, its timestamp, and the\n sender's user ID to the conversation history. The user ID can be any string that\n uniquely identifies the sender within the conversation. The user ID doesn't need\n to correspond to any user data, and the user ID doesn't need to be consistent\n between conversation or invocations of the smart reply generator. \n\n Kotlin \n\n ```kotlin\n conversation.add(TextMessage.createForRemoteUser(\n \"Are you coming back soon?\", System.currentTimeMillis(), userId))\n ```\n\n Java \n\n ```java\n conversation.add(TextMessage.createForRemoteUser(\n \"Are you coming back soon?\", System.currentTimeMillis(), userId));\n ```\n\n A conversation history object looks like the following example:\n\n | Timestamp | userID | isLocalUser | Message |\n |------------------------------|---------|-------------|----------------------|\n | Thu Feb 21 13:13:39 PST 2019 | | true | are you on your way? |\n | Thu Feb 21 13:15:03 PST 2019 | FRIEND0 | false | Running late, sorry! |\n\n ML Kit suggests replies to the last message in a conversation history. The last message\n should be from a non-local user. In the example above, the last message in the conversation\n is from the non-local user FRIEND0. When you use pass ML Kit this log, it suggests\n replies to FRIENDO's message: \"Running late, sorry!\"\n\n 2. Get message replies\n\n To generate smart replies to a message, get an instance of `SmartReplyGenerator`\n and pass the conversation history to its `suggestReplies()` method: \n\n Kotlin \n\n ```kotlin\n val smartReplyGenerator = SmartReply.getClient()\n smartReply.suggestReplies(conversation)\n .addOnSuccessListener { result -\u003e\n if (result.getStatus() == SmartReplySuggestionResult.STATUS_NOT_SUPPORTED_LANGUAGE) {\n // The conversation's language isn't supported, so\n // the result doesn't contain any suggestions.\n } else if (result.getStatus() == SmartReplySuggestionResult.STATUS_SUCCESS) {\n // Task completed successfully\n // ...\n }\n }\n .addOnFailureListener {\n // Task failed with an exception\n // ...\n }\n ```\n\n Java \n\n ```java\n SmartReplyGenerator smartReply = SmartReply.getClient();\n smartReply.suggestReplies(conversation)\n .addOnSuccessListener(new OnSuccessListener() {\n @Override\n public void onSuccess(SmartReplySuggestionResult result) {\n if (result.getStatus() == SmartReplySuggestionResult.STATUS_NOT_SUPPORTED_LANGUAGE) {\n // The conversation's language isn't supported, so\n // the result doesn't contain any suggestions.\n } else if (result.getStatus() == SmartReplySuggestionResult.STATUS_SUCCESS) {\n // Task completed successfully\n // ...\n }\n }\n })\n .addOnFailureListener(new OnFailureListener() {\n @Override\n public void onFailure(@NonNull Exception e) {\n // Task failed with an exception\n // ...\n }\n });\n ```\n\n If the operation succeeds, a `SmartReplySuggestionResult` object is passed to\n the success handler. This object contains a list of up to three suggested replies,\n which you can present to your user: \n\n Kotlin \n\n ```kotlin\n for (suggestion in result.suggestions) {\n val replyText = suggestion.text\n }\n ```\n\n Java \n\n ```java\n for (SmartReplySuggestion suggestion : result.getSuggestions()) {\n String replyText = suggestion.getText();\n }\n ```\n\n Note that ML Kit might not return results if the model isn't confident in\n the relevance of the suggested replies, the input conversation isn't in\n English, or if the model detects sensitive subject matter."]]
