Limits - IoT Platform - Alibaba Cloud Documentation Center

This topic describes the limits that apply when you use IoT Platform.

Device connection

Product quantity

Region	Description	Limit
Singapore, Germany (Frankfurt), US (Silicon Valley), and US (Virginia)	The maximum number of products that you can create by using an Alibaba Cloud account.	1,000
China (Shanghai) and Japan (Tokyo)	The maximum number of products that you can create for an instance.	1,000

Device quantity

Note

If you want to increase the limit based on your business requirements, submit a ticket.

The maximum number of devices that can be added to a product.
Region
Limit
China (Shanghai)
3,000,000
Singapore, Germany (Frankfurt), US (Silicon Valley), US (Virginia), and Japan (Tokyo)
1,000,000
Note
To ensure that new devices can be added to a product, we recommend that you configure a threshold alert for the number of devices that you have added to the product. This way, you can obtain the number of existing devices in the product in real time. For more information, see Create a threshold-triggered alert rule.
If the number of devices exceeds the limit, create another product.

The maximum number of devices that can be added to an instance.

Region	Instance type	Limit
China (Shanghai)	Public instances of the previous version and Enterprise Edition instances	1,000,000
China (Shanghai)	Public instances of the new version	500
Singapore, Germany (Frankfurt), US (Silicon Valley), and US (Virginia)	This limit applies only to public instances because Enterprise Edition instances are not available in these regions.	You can refer to the limit on the number of devices that you can add by using an Alibaba Cloud account.
Japan (Tokyo)	Enterprise Edition instances and public instances	1,000,000

Note

For more information about how to purchase an Enterprise Edition instance, see Purchase Enterprise Edition instances.
If the value that you selected for the device quantity specification of an Enterprise Edition instance that you purchased is less than this limit, you can upgrade the specification of the instance. For more information, see Upgrade instance specifications.
If the number of devices that you want to create for a public instance of the new version exceeds 500, we recommend that you upgrade the public instance to an Enterprise Edition instance. For more information, see Upgrade a public instance of the new version to an Enterprise Edition instance.

The maximum number of devices that you can add by using an Alibaba Cloud account.

Region	Limit
China (Shanghai) and Japan (Tokyo)	None. You can refer to the limit on the number of devices that you can add to an instance.
Singapore, Germany (Frankfurt), US (Silicon Valley), and US (Virginia)	10,000,000

Quantities of sub-devices attached to a gateway
- You can attach a maximum of 2,000 sub-devices to a gateway.
- You can dynamically register up to 30 sub-devices for a gateway at a time.
- You can send a request to connect or disconnect up to 50 sub-devices to or from a gateway at a time.
- A gateway can initiate a maximum of 200 queries per second (QPS) to connect sub-devices to IoT Platform.
For more information about throttling limits, see the Messages item in the Connections and communications section.

Device management

Item	Description	Limit
Thing Specification Language (TSL) features	The maximum number of TSL modules that can be created for a product, including the default modules and custom modules.	20
	The maximum number of features that can be added to a TSL module.	300
	The maximum number of parameters that can be specified for a property of the STRUCT data type.	50
	The maximum number of items that can be specified for a feature of the ENUM data type.	100
	The maximum length that can be specified for a feature of the TEXT data type.	10,240 characters
	The maximum number of elements that can be specified for a feature of the ARRAY data type.	512
	The maximum number of input parameters and output parameters that can be added to all services and events.	300
	The maximum number of input parameters that can be added to a service.	100
	The maximum number of output parameters that can be added to a service.	100
	The maximum number of output parameters that can be added to an event.	100
	The maximum number of TSL module files that can be imported at the same time.	20
	The maximum number of latest versions that can be saved for a TSL model.	10
	The maximum size of an imported TSL module in the JSON format.	512 KB
	The maximum number of valid characters that can be contained in an imported TSL module in the JSON format. Valid characters do not include line feeds and alignment characters.	256 KB
	The maximum size of a ZIP file that can be obtained by compressing multiple JSON-formatted files when you import a TSL model.	2.5 MB
	The maximum number of recursive nesting levels that are supported if you nest data of the ARRAY and STRUCT data types for the ThingModelJson parameter when you call TSL-related operations. For example, you can nest data of the STRUCT type only in data of the ARRAY type. The data of the STRUCT type cannot contain data of the ARRAY or STRUCT type.	2
Tags	The maximum number of tags that can be attached to a product, device, or device group.	100
Device groups	The maximum number of groups and sub-groups that each Alibaba Cloud account can create.	1,000
	The maximum number of devices that can be added to a group.	100,000
	The maximum number of groups to which a device can be added.	10
Data parsing	The maximum size of a data parsing script.	128 KB
Remote configuration	The maximum size of a remote configuration file. Remote configuration files support only the JSON format.	64 KB
Retention period of TSL data	The maximum number of days for which property data, event data, and service data can be retained. Data is deleted after the retention period ends.	30
File management	The maximum size of files that can be stored in an instance.	1 GB
	The maximum size of a single file that can be uploaded by a device over Message Queuing Telemetry Transport (MQTT).	16 MB
	The maximum number of files that can be stored on a device.	1,000
Over-the-air (OTA) update	The maximum number of update packages that you can add to an instance of an Alibaba Cloud account.	500
	The maximum size of an OTA update package when you download OTA update packages over HTTPS. If you want to increase the limit based on your business requirements, submit a ticket. The limit cannot exceed 2,000 MB.	1,000 MB
	The maximum size of an OTA update package when you download OTA update packages over MQTT. An OTA update package can contain only one file.	16 MB
	The maximum number of devices that can be specified for a batch update. Important If you upload a device list file to update the devices whose names are specified in the file, you can update up to 1,000,000 devices at a time. If you want to increase the limit based on your business requirements, submit a ticket.	100,000
Device jobs	The maximum number of device jobs that each Alibaba Cloud account can add in a single region.	10,000

Connections and communications

Item	Description	Limit
Device connections	The maximum number of connections that can be established with IoT Platform by using the same device certificate information. The device certificate information includes the ProductKey and DeviceName parameters.	1
Connection requests	The maximum number of MQTT connection requests that each Alibaba Cloud account can initiate per second.	500
Connection requests	The maximum number of connection requests that a device can send per minute without being throttled.	5
Topic subscription by devices	The maximum number of topics to which a device can subscribe. After the limit is reached, new subscription requests are rejected. The device can check whether a subscription request succeeds by verifying the SUBACK message.	100
Requests	The maximum number of requests that the devices of a public instance of an Alibaba Cloud account can send to IoT Platform per second.	10,000
	The maximum number of requests that IoT Platform can send to the devices of a public instance of an Alibaba Cloud account per second.	2,000
	The maximum number of requests that an Enterprise Edition instance can send to and receive from IoT Platform per second. The value varies based on the specified value of the TPS of Upstream & Downstream Messages specification when you purchased the instance. For more information about how to purchase an Enterprise Edition instance, see Purchase Enterprise Edition instances.	View the available resources of an instance
Messages	The maximum number of QoS 0 or QoS 1 messages that a device can send to IoT Platform per second. Note If you use the MQTT protocol to publish messages, no throttling information is returned. You can view device logs to find the devices whose messages are blocked due to throttling.	30
Messages	The maximum number of messages that a device can receive per second. The limit varies based on the network environment. If the maximum size of the TCP write buffer is exceeded, an error message is returned. If IoT Platform calls the Pub operation to send requests to a device but the device cannot process the requests at the earliest opportunity, a throttling error message is returned.	50
Bandwidth	The maximum throughput (bandwidth) per connection.	8 Mbps
Cached requests	The maximum number of unacknowledged message publishing requests from a device. After the limit is reached, IoT Platform rejects new message publishing requests from the device until a PUBACK message is received.	100
Message retention period	The maximum number of days for which a QoS 1 message can be retained. If no PUBACK message is received before the maximum retention period ends, the message publishing request is rejected.	7
MQTT message size	The maximum size of a message that can be sent over MQTT. Messages whose sizes exceed this limit are discarded.	256 KB
CoAP message size	The maximum size of a message that can be sent over CoAP. Messages whose sizes exceed this limit are discarded.	1 KB
MQTT keep-alive mechanism	The heartbeat interval for an MQTT connection ranges from 30 to 1,200 seconds. If a heartbeat interval does not fall in the specified value range, the server rejects the connection request. We recommend that you specify an interval that is greater than 300 seconds. Default value: 1200. Unit: seconds. For more information about how to specify a heartbeat interval for a device, see Example. A timer starts when IoT Platform sends a CONNACK message as a response to a CONNECT message. When IoT Platform receives a PUBLISH, SUBSCRIBE, PING, or PUBACK message, the timer is reset. IoT Platform checks the heartbeat of the MQTT connection every 30 seconds. The wait time for the heartbeat check is the period between the point in time at which a device connects to IoT Platform and the point in time at which the next heartbeat check is performed. The maximum timeout period is calculated by using the following formula: `Heartbeat interval × 1.5 + Wait time for the heartbeat check`. If the server receives no messages from the device within the maximum timeout period, the server ends the connection with the device.	30 to 1,200 seconds
RRPC timeout period	The timeout period during which devices must respond to RRPC requests.	8 seconds
Properties	The maximum number of properties that a device can submit at the same time.	500
Historical properties and events	The maximum number of devices that can submit historical TSL data at the same time. This limit applies only to the devices that belong to the same instance.	50
	The maximum number of properties that a device can submit at the same time.	30
	The maximum number of events that a device can submit at the same time.	20
Batch submission of properties and events	The maximum number of property and event entries that a device can submit at a time. An entry includes a property name and a property value, or an event name and an event value.	1,000
MQTT 5.0 protocol	The maximum number of custom properties that can be added.	20
	The maximum length of a custom property key or custom property value.	128 characters
	The maximum length of the ResponseTopic parameter or CorrelationData parameter that can be configured in the request/response communication mode.	128 characters

Topics

Item	Description	Limit
Custom topic categories	The maximum number of topic categories that can be defined for a product.	200
Permissions	A device can publish messages and subscribe only to the topics that are associated with the device.	None
Topic length	The maximum length of a topic that is encoded in UTF-8.	128 bytes
Topic levels	The maximum number of category levels that can be included in a topic. The number of category levels is equal to the number of slashes (/) in the topic.	7
Topics in a subscription request	The maximum number of topics that can be included in a subscription request.	8
Time to take effect	The period of time that a subscribe operation or unsubscribe operation requires to take effect. A subscription remains valid until you unsubscribe the device from the topic. We recommend that the device subscribe to topics in advance to prevent information missing. For example, a device sends a subscription request to Topic A. After 10 seconds, the subscription takes effect and the device starts to receive messages from Topic A in real time. The device continues to receive messages from Topic A until you unsubscribe the device from the topic.	10 seconds
Message broadcasting	The maximum size of a message that can be broadcasted. To generate a message body, you must convert a raw message into binary data and encode the data by using Base64.	64 KB
Message broadcasting	The number of messages that can be broadcasted per minute by using the server SDK.	1

Device shadows

Item	Description	Limit
JSON levels	The maximum number of levels that can be included in the JSON file of a device shadow.	5
File size	The maximum size of a device shadow JSON file.	16 KB
Properties	The maximum number of properties that can be specified in a device shadow JSON file.	128
QPS	The maximum number of requests that a device can send per second.	20

Data forwarding (old version)

Item	Description	Limit
Rules	The maximum number of rules that each Alibaba Cloud account can create.	1,000
Data forwarding destinations	The maximum number of data forwarding actions that you can specify in a rule.	10
Messages processed by the rules engine	The maximum number of data forwarding queries that can be processed per second for a public instance of an Alibaba Cloud account. The RAM users of an Alibaba Cloud account share the quota of the account. The maximum number of messages that the rules engine can process for an Enterprise Edition instance. The value varies based on the specified value of the Rules Engine TPS specification. For more information about how to purchase an Enterprise Edition instance, see Purchase Enterprise Edition instances. After a message is processed, it can be written to multiple Alibaba Cloud services. For more information, see the next item: Messages written to Alibaba Cloud services. If a message is blocked due to throttling, IoT Platform retries to process the message. If multiple retries fail, the message is discarded.	Public instances: 1,000 TPS Enterprise Edition instances: View the available resources of an instance
Messages written to Alibaba Cloud services	The maximum number of data forwarding queries that can be processed per second for a public instance of an Alibaba Cloud account. The maximum number can be reached only if the instance of an Alibaba Cloud service provides a high level of performance. The maximum number of messages that the rules engine can write from an Enterprise Edition instance to an Alibaba Cloud service. The value varies based on the specified value of the Rules Engine TPS specification. For more information about how to purchase an Enterprise Edition instance, see Purchase Enterprise Edition instances. The RAM users of an Alibaba Cloud account share the quota of the account. If the limit is exceeded or if the number of concurrent write requests to an Alibaba Cloud service exceeds 40, data forwarding fails due to throttling. If a destination service such as Message Queue for Apache RocketMQ, ApsaraDB RDS, or ApsaraDB for Lindorm is unavailable due to the resource changes of the service, IoT Platform stops forwarding messages and displays the abnormal rule. If an error occurs due to another cause when you send a message, IoT Platform retries three times at the intervals of 1, 3, and 10 seconds. If all retries fail, the message is discarded and an error message is sent to the destination cloud service.	Public instances: 2,000 TPS Enterprise Edition instances: View the available resources of an instance
Requirements of data forwarding destinations	Make sure that the instance of the destination cloud service runs as expected. Data forwarding fails in multiple scenarios. These scenarios include instance failure, overdue payments, improper configurations, and invalid parameter settings, such as invalid values and lack of permissions.	None
Message deduplication	When you forward a message, the message may be repeatedly sent until the client returns an ACK message or the message expires. If multiple messages use the same message ID, you can deduplicate the messages based on the ID.	None

Data forwarding (new version)

The limits on the messages related to Data forwarding (old version) are the same as the limits on the messages related to data forwarding (new version).

Item	Description	Limit
Parser	The maximum number of parsers that an instance can contain.	1,000
Data source	The maximum number of data sources that can be associated with a parser.	1
Data source	The maximum number of topics that a data source can contain.	1,000
Data destination	The maximum number of data destinations that can be associated with a parser.	10
	The maximum number of operations that a data destination can contain.	1
	The maximum number of error data destinations that can be associated with a parser.	1
Parser script	The maximum size of a parser script.	120 KB
Parser script	The maximum number of times that a data forwarding function can be executed in a loop in a parser script. For more information about data forwarding functions, see Forward data to destinations.	100

Server-side subscription

The following table describes the limits on Advanced Message Queuing Protocol (AMQP) server-side subscription.

Item	Description
Authentication timeout	After a connection is established, an authentication request is immediately sent. If the authentication fails within 15 seconds, the server closes the connection.
Data timeout	When a server establishes a connection to IoT Platform, the heartbeat timeout period must be specified by using the idle-timeout parameter in AMQP. The timeout period ranges from 30 to 300 seconds. If no frames are transmitted within the heartbeat timeout period, IoT Platform closes the connection. After the connection is established, the server must send ping packets within the heartbeat timeout period to maintain the connection. If the server does not send ping packets within the heartbeat timeout period, IoT Platform closes the connection. Note If the connection is established by using an Alibaba Cloud SDK, the server does not need to send ping packets to maintain the connection. Make sure that the main process does not exit during the keep-alive period that is provided by the SDK.
ACK timeout	If an AMQP server fails to receive a message from a client within 30 seconds after the AMQP server forwards a message to the client, an ACK timeout occurs.
Policy for message pushing retries	Messages may fail to be consumed in real time when consumers disconnect from IoT Platform or consume messages at a low speed. In this case, messages are accumulated in a queue. After the consumers re-connect to IoT Platform or restore the stable message consumption speed, IoT Platform pushes accumulated messages to the consumers. If the consumers fail to consume the pushed messages, the queue in which the accumulated messages reside may be blocked. If the messages fail to be consumed, IoT Platform retries to push the accumulated messages to the consumers after approximately 1 minute.
Maximum number of saved messages	Each consumer group can retain up to 100 million messages.
Message retention period	One day.
Maximum push rate for real-time messages	Each connection can be used to process up to 1,000 transactions per second (TPS). Up to 64 connections can be established.
Maximum push rate for accumulated messages	A consumer group can process up to 200 TPS. Note To prevent a large number of accumulated messages, make sure that consumers are connected to IoT Platform. In addition, the consumers must send ACK responses to messages that are pushed by IoT Platform.
Maximum number of consumer groups with which a product can be associated	10.
Maximum number of products with which a consumer group can be associated	1,000.
Maximum number of topics to which a consumer group can subscribe	200. Note A topic whose name contains wildcard characters can represent multiple topics but is counted only as one topic. For example, if a consumer group subscribes to the`/asde**/+/user/get` topic of the asde** product, all topics of devices that belong to the product are subscribed but are not counted.
Maximum number of consumer groups	Each Alibaba Cloud account can create up to 1,000 consumer groups.
Maximum number of consumers	Each consumer group can have up to 64 consumers.
Maximum connection requests	Each consumer can initiate up to 100 connection requests within 1 minute. Note Consumers are not devices but AMQP clients that are used to receive IoT Platform messages.

For more information about the limits on Message Service (MNS) server-side subscription, see the limits on MNS queues in MNS limits.

IoT Platform API operations

The maximum QPS for the IoT Platform API. For more information, see List of API operations by function.

If a throttling error message is returned when you call an operation, retry to call the operation. For more information about throttling errors, see Common errors. Errors 28 to 30 are throttling errors.