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
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.
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 10 phrase lists, 5,000 items per list
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 no limit
Version name 10 characters restricted to alphanumeric and period (.)

*Default character max is 50 characters.

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.

Key limits

The authoring key has different limits for authoring and endpoint. The LUIS service endpoint key is only valid for endpoint queries.

Key Authoring Endpoint Purpose
Language Understanding Authoring/Starter 1 million/month, 5/second 1 thousand/month, 5/second Authoring your LUIS app
Language Understanding Subscription - F0 - Free tier invalid 10 thousand/month, 5/second Querying your LUIS endpoint
Language Understanding Subscription - S0 - Basic tier invalid 50/second Querying your LUIS endpoint
Cognitive Service Subscription - S0 - Standard tier invalid 50/second Querying your LUIS endpoint
Sentiment analysis integration invalid no charge Adding sentiment information including key phrase data extraction
Speech integration invalid $5.50 USD/1 thousand endpoint requests Convert spoken utterance to text utterance and return LUIS results

Keyboard controls

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

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