Azure Digital Twins service limits

The following sections describe the service limits of Azure Digital Twins.

Note

Some areas of this service have adjustable limits. This is represented in the tables below with the Adjustable? column. When the limit can be adjusted, the Adjustable? value is Yes.

If your business requires raising an adjustable limit or quota above the default limit, you can request additional resources by opening a support ticket.

Limits by type

Functional limits

The following table lists the functional limits of Azure Digital Twins.

Tip

For modeling recommendations to operate within these functional limits, see Modeling tools and best practices.

Area Capability Default limit Adjustable?
Azure resource Number of Azure Digital Twins instances in a region, per subscription 10 Yes
Digital twins Number of twins in an Azure Digital Twins instance 2,000,000 Yes
Digital twins Number of incoming relationships to a single twin 5,000 No
Digital twins Number of outgoing relationships from a single twin 5,000 No
Digital twins Maximum size (of JSON body in a PUT or PATCH request) of a single twin 32 KB No
Digital twins Maximum request payload size 32 KB No
Digital twins Maximum size of a string property value (UTF-8) 4 KB No
Digital twins Maximum size of a property name 1 KB No
Routing Number of endpoints for a single Azure Digital Twins instance 6 No
Routing Number of routes for a single Azure Digital Twins instance 6 Yes
Models Number of models within a single Azure Digital Twins instance 10,000 Yes
Models Number of models that can be uploaded in a single API call 250 No
Models Maximum size (of JSON body in a PUT or PATCH request) of a single model 1 MB No
Models Number of items returned in a single page 100 No
Query Number of items returned in a single page 1000 Yes
Query Number of AND / OR expressions in a query 50 Yes
Query Number of array items in an IN / NOT IN clause 50 Yes
Query Number of characters in a query 8,000 Yes
Query Number of JOINS in a query 5 Yes

Rate limits

The following table reflects the rate limits of different APIs.

API Capability Default limit Adjustable?
Models API Number of requests per second 100 Yes
Digital Twins API Number of read requests per second 1,000 Yes
Digital Twins API Number of patch requests per second 1,000 Yes
Digital Twins API Number of create/delete operations per second across all twins and relationships 50 Yes
Digital Twins API Number of create/update/delete operations per second on a single twin or its incoming/outgoing relationships 10 No
Digital Twins API Number of outstanding operations on a single twin or its incoming/outgoing relationships 500 No
Query API Number of requests per second 500 Yes
Query API Query Units per second 4,000 Yes
Event Routes API Number of requests per second 100 Yes

Other limits

Limits on data types and fields within DTDL documents for Azure Digital Twins models can be found within its spec documentation in GitHub: Digital Twins Definition Language (DTDL) - version 2.

Query latency details are described in Query language. Limitations of particular query language features can be found in the query reference documentation.

Working with limits

When a limit is reached, any requests beyond it are throttled by the service, which will result in a 429 error response from these requests.

To manage the throttling, here are some recommendations for working with limits.

  • Use retry logic. The Azure Digital Twins SDKs implement retry logic for failed requests, so if you're working with a provided SDK, this functionality is already built-in. Otherwise, consider implementing retry logic in your own application. The service sends back a Retry-After header in the failure response, which you can use to determine how long to wait before retrying.
  • Use thresholds and notifications to warn about approaching limits. Some of the service limits for Azure Digital Twins have corresponding metrics that can be used to track usage in these areas. To configure thresholds and set up an alert on any metric when a threshold is approached, see the instructions in Create a new alert rule. To set up notifications for other limits where metrics aren't provided, consider implementing this logic in your own application code.
  • Deploy at scale across multiple instances. Avoid having a single point of failure. Instead of one large graph for your entire deployment, consider sectioning out subsets of twins logically (like by region or tenant) across multiple instances.

Note

Azure Digital Twins will automatically scale resources to meet the rate limits described in this article. You may experience throttling before these limits are reached due to internal scaling to adapt to the incoming load. Internal scaling can take anywhere from 5 to 30 minutes, during which time your application may encounter 429 errors.

Next steps

Learn more about the current release of Azure Digital Twins in the service overview: