[Yandex Cloud documentation](../../index.md) > [Yandex IoT Core](../index.md) > [Concepts](index.md) > Quotas and limits

# Yandex IoT Core quotas and limits

{% note warning %}

Yandex IoT Core is no longer available to new users. 

Current users can create resources until November 1, 2026. Afterwards, the service will go read-only and cease to operate on December 1, 2026. For more information on the timing and procedure, see [Service shutdown](../sunset.md).

{% endnote %}

Yandex IoT Core has the following limitations:

* [_Quotas_](https://console.yandex.cloud/cloud?section=quotas) are organizational constraints that can be changed by contacting technical support.
* _Limits_ are technical constraints of the Yandex Cloud architecture. You cannot change the limits.

If you need more resources, you can increase your quotas in one of the following ways:

* [Make a request to increase your quotas](https://console.yandex.cloud/cloud?section=quotas).
* Contact [support](https://center.yandex.cloud/support) and specify which quotas you want increased and by how much.

To have your request processed, you must have the `quota-manager.requestOperator` [role](../../iam/roles-reference.md#quota-manager-requestoperator) or higher, e.g., `editor` or `admin`.

You can manage your quotas with [Cloud Quota Manager](../../quota-manager/quickstart.md).

#### Quotas {#iot-quotas}

#|
|| Type of limit | Value ||
|| Number of registries per cloud 
`iot.registries.count` | 10 ||
|| Number of devices per cloud 
`iot.devices.count`| 1,000 ||
|| Number of brokers per cloud 
`iot.brokers.count` | 10 ||
|| Frequency of sending messages per broker 
`iot.brokerMessaging.rate` | 50 per second ||
|| Number of clients concurrently connected to the broker 
`iot.brokerConnections.count` | 50 ||
|#


#### Limits {#iot-limits}

Type of limit | Value
----- | -----
Maximum size per message | 256 KB
Frequency of sending messages per device | No more than once per second
Maximum [subtopic](topic/subtopic.md) name length | 1,024 characters
Maximum number of [aliases](topic/usage.md#aliases) per device | 5

{% note info %}

Message delivery is not guaranteed if the limits are exceeded.

{% endnote %}


#### Other restrictions {#iot-other-restrictions}

* The `Retain` flag is not supported. This flag enables the MQTT broker to save the flagged message and send it when subscribing to the topic next time.
* Persistent sessions, when the MQTT broker saves information about a client (device or registry) to reconnect faster, are not supported.
* The `QoS 2: Exactly once` quality of service level for MQTT is not supported.
* There is no guarantee that the devices or registries with the same [ClientID](https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html#_Toc385349242) cannot connect to the MQTT broker at the same time.