Prediction endpoint changes for V3

The query prediction endpoint V3 APIs have changed. Use this guide to understand how to migrate to version 3 endpoint APIs.

Generally available status - this V3 API include significant JSON request and response changes from V2 API.

The V3 API provides the following new features:

The prediction endpoint request and response have significant changes to support the new features listed above, including the following:

Reference documentation is available for V3.

V3 changes from preview to GA

V3 made the following changes as part of the move to GA:

  • The following prebuilt entities have different JSON responses:

  • Request body JSON change:

    • from preferExternalEntities to preferExternalEntities
    • optional score parameter for external entities
  • Response body JSON changes:

    • normalizedQuery removed

Suggested adoption strategy

If you use Bot Framework, Bing Spell Check V7, or want to migrate your LUIS app authoring only, continue to use the V2 endpoint.

If you know none of your client application or integrations (Bot Framework, and Bing Spell Check V7) are impacted and you are comfortable migrating your LUIS app authoring and your prediction endpoint at the same time, begin using the V3 prediction endpoint. The V2 prediction endpoint will still be available and is a good fall-back strategy.

Not supported

Bing Spell Check

This API is not supported in V3 prediction endpoint - continue to use V2 API prediction endpoint for spelling corrections. If you need spelling correction while using V3 API, have the client application call the Bing Spell Check API, and change the text to the correct spelling, prior to sending the text to the LUIS API.

Bot Framework and Azure Bot Service client applications

Continue to use the V2 API prediction endpoint until the V4.7 of the Bot Framework is released.

V2 API Deprecation

The V2 prediction API will not be deprecated for at least 9 months after the V3 preview, June 8th, 2020.

Endpoint URL changes

Changes by slot name and version name

The format of the V3 endpoint HTTP call has changed.

If you want to query by version, you first need to publish via API with "directVersionPublish":true. Query the endpoint referencing the version ID instead of the slot name.

Valid values for SLOT-NAME

Request changes

Query string changes

V3 API query string parameters include:

Query parameter LUIS portal name Type Version Default Purpose
log Save logs boolean V2 & V3 false Store query in log file. Default value is false.
query - string V3 only No default - it is required in the GET request In V2, the utterance to be predicted is in the q parameter.

In V3, the functionality is passed in the query parameter.
show-all-intents Include scores for all intents boolean V3 only false Return all intents with the corresponding score in the prediction.intents object. Intents are returned as objects in a parent intents object. This allows programmatic access without needing to find the intent in an array: prediction.intents.give. In V2, these were returned in an array.
verbose Include more entities details boolean V2 & V3 false In V2, when set to true, all predicted intents were returned. If you need all predicted intents, use the V3 param of show-all-intents.

In V3, this parameter only provides entity metadata details of entity prediction.
timezoneOffset - string V2 - Timezone applied to datetimeV2 entities.
datetimeReference - string V3 - Timezone applied to datetimeV2 entities. Replaces timezoneOffset from V2.

V3 POST body

    "query":"your utterance here",
        "datetimeReference": "2019-05-05T12:00:00",
        "preferExternalEntities": true
Property Type Version Default Purpose
dynamicLists array V3 only Not required. Dynamic lists allow you to extend an existing trained and published list entity, already in the LUIS app.
externalEntities array V3 only Not required. External entities give your LUIS app the ability to identify and label entities during runtime, which can be used as features to existing entities.
options.datetimeReference string V3 only No default Used to determine datetimeV2 offset. The format for the datetimeReference is ISO 8601.
options.preferExternalEntities boolean V3 only false Specifies if user's external entity (with same name as existing entity) is used or the existing entity in the model is used for prediction.
query string V3 only Required. In V2, the utterance to be predicted is in the q parameter.

In V3, the functionality is passed in the query parameter.

Response changes

The query response JSON changed to allow greater programmatic access to the data used most frequently.

Top level JSON changes

The top JSON properties for V2 are, when verbose is set to true, which returns all intents and their scores in the intents property:

    "query":"this is your utterance you want predicted",

The top JSON properties for V3 are:

    "query": "this is your utterance you want predicted",
        "topIntent": "intent-name-1",
        "intents": {},

The intents object is an unordered list. Do not assume the first child in the intents corresponds to the topIntent. Instead, use the topIntent value to find the score:

const topIntentName = response.prediction.topIntent;
const score = intents[topIntentName];

The response JSON schema changes allow for:

  • Clear distinction between original utterance, query, and returned prediction, prediction.
  • Easier programmatic access to predicted data. Instead of enumerating through an array in V2, you can access values by name for both intents and entities. For predicted entity roles, the role name is returned because it is unique across the entire app.
  • Data types, if determined, are respected. Numerics are no longer returned as strings.
  • Distinction between first priority prediction information and additional metadata, returned in the $instance object.

Entity response changes

Marking placement of entities in utterances

In V2, an entity was marked in an utterance with the startIndex and endIndex.

In V3, the entity is marked with startIndex and entityLength.

Access $instance for entity metadata

If you need entity metadata, the query string needs to use the verbose=true flag and the response contains the metadata in the $instance object. Examples are shown in the JSON responses in the following sections.

Each predicted entity is represented as an array

The prediction.entities.<entity-name> object contains an array because each entity can be predicted more than once in the utterance.

Prebuilt entity changes

The V3 response object includes changes to prebuilt entities. Review specific prebuilt entities to learn more.

List entity prediction changes

The JSON for a list entity prediction has changed to be an array of arrays:


Each interior array corresponds to text inside the utterance. The interior object is an array because the same text can appear in more than one sublist of a list entity.

When mapping between the entities object to the $instance object, the order of objects is preserved for the list entity predictions.

const item = 0; // order preserved, use same enumeration for both
const predictedCanonicalForm = entities.my_list_entity[item];
const associatedMetadata = entities.$instance.my_list_entity[item];

Entity role name instead of entity name

In V2, the entities array returned all the predicted entities with the entity name being the unique identifier. In V3, if the entity uses roles and the prediction is for an entity role, the primary identifier is the role name. This is possible because entity role names must be unique across the entire app including other model (intent, entity) names.

In the following example: consider an utterance that includes the text, Yellow Bird Lane. This text is predicted as a custom Location entity's role of Destination.

Utterance text Entity name Role name
Yellow Bird Lane Location Destination

In V2, the entity is identified by the entity name with the role as a property of the object:

        "entity": "Yellow Bird Lane",
        "type": "Location",
        "startIndex": 13,
        "endIndex": 20,
        "score": 0.786378264,
        "role": "Destination"

In V3, the entity is referenced by the entity role, if the prediction is for the role:

        "Yellow Bird Lane"

In V3, the same result with the verbose flag to return entity metadata:

        "Yellow Bird Lane"
        "Destination": [
                "role": "Destination",
                "type": "Location",
                "text": "Yellow Bird Lane",
                "startIndex": 25,
                "score": 0.9837309,
                "modelTypeId": 1,
                "modelType": "Entity Extractor"

Extend the app at prediction time

Learn concepts about how to extend the app at prediction runtime.


The V2 API will not be deprecated for at least 9 months after the V3 preview.

Next steps

Use the V3 API documentation to update existing REST calls to LUIS endpoint APIs.