Boundaries for your LUIS model and keys

LUIS has several boundary areas. The first is the model boundary, which controls intents, entities, and features in LUIS. The second area is quota limits based on key type. A third area of boundaries is the keyboard combination for controlling the LUIS website. A fourth area is the world region mapping between the LUIS authoring website and the LUIS endpoint APIs.

Model boundaries

If your app exceeds the LUIS model limits and boundaries, consider using a LUIS dispatch app or using a LUIS container.

Area Limit
App name *Default character max
Applications 500 applications per Azure authoring resource
Batch testing 10 datasets, 1000 utterances per dataset
Explicit list 50 per application
External entities no limits
Intents 500 per application: 499 custom intents, and the required None intent.
Dispatch-based application has corresponding 500 dispatch sources.
List entities Parent: 50, child: 20,000 items. Canonical name is *default character max. Synonym values have no length restriction.
Machine-learned entities + roles:
entity role
A limit of either 100 parent entities or 330 entities, whichever limit the user hits first. A role counts as an entity for the purpose of this boundary. An example is a composite with a simple entity, which has 2 roles is: 1 composite + 1 simple + 2 roles = 4 of the 330 entities.
Subcomponents can be nested up to 5 levels.
Model as a feature Maximum number of models that can be used as a descriptor (feature) to a specific model to be 10 models. The maximum number of phrase lists used as a descriptor (feature) for a specific model to be 10 phrase lists.
Preview - Dynamic list entities 2 lists of ~1k per query prediction endpoint request
Patterns 500 patterns per application.
Maximum length of pattern is 400 characters.
3 Pattern.any entities per pattern
Maximum of 2 nested optional texts in pattern
Pattern.any 100 per application, 3 pattern.any entities per pattern
Phrase list 500 phrase lists. Non-interchangeable phraselist has max of 5,000 phrases. Interchangeable Phraselist has max of 50,000 phrases. Maximum number of total phrases per application of 500,000 phrases.
Prebuilt entities no limit
Regular expression entities 20 entities
500 character max. per regular expression entity pattern
Roles 300 roles per application. 10 roles per entity
Utterance 500 characters
Utterances 15,000 per application - there is no limit on the number of utterances per intent
Versions 100 versions per application
Version name 10 characters restricted to alphanumeric and period (.)

*Default character max is 50 characters.

Name uniqueness

Use the following naming uniqueness rules.

The following must be unique within a LUIS app:

  • version name
  • intent
  • entity
  • roles

The following must be unique within the scope applied:

  • phrase list

Object naming

Do not use the following characters in the following names.

Object Exclude characters
Intent, entity, and role names :
Version name \

Key usage

Language Understand has separate keys, one type for authoring, and one type for querying the prediction endpoint. To learn more about the differences between key types, see Authoring and query prediction endpoint keys in LUIS.

Resource key limits

The resource keys have different limits for authoring and endpoint. The LUIS prediction query endpoint key is only valid for endpoint queries.

  • 500 applications per Azure authoring resource
Key Authoring Endpoint Purpose
Starter 1 million/month, 5/second 1 thousand/month, 5/second Authoring your LUIS app
F0 - Free tier 1 million/month, 5/second 10 thousand/month, 5/second Querying your LUIS endpoint
S0 - Basic tier - 50/second Querying your LUIS endpoint
S0 - Standard tier - 50/second Querying your LUIS endpoint
Sentiment analysis integration - - Adding sentiment information including key phrase data extraction is provided without requiring another Azure resource.
Speech integration - 1 thousand endpoint requests per unit cost Convert spoken utterance to text utterance and return LUIS results

Learn more about pricing.

Keyboard controls

Keyboard input Description
Control+E switches between tokens and entities on utterances list

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