FAQ

• What is included in the IoT Hub Free Edition?

  The IoT Hub Free Edition is intended to encourage proof of concept projects. It enables you to transmit up to a total of 8,000 messages per day, and register up to 500 device identities. The device identity limit is only present for the Free Edition.

• How can I scale up or scale down the number of IoT Hub units I have purchased?

  Every tier has daily message limit after which you will experience throttling. Please check throttling documentation for more details. If your need change, you can adjust the units within IoT Hub. You can also change the unit type within a tier (e.g.: from S1 to S2) or upgrade to a higher tier (e.g.: B1 to S2). If you anticipate using more than 200 units of the IoT Hub S1 S2 SKU’s and IoT Hub B1 B2 SKU’s or more than 10 units of the IoT Hub B3 or S3 please contact Microsoft Support.

• What is the maximum size of message that I can send through the IoT Hub?

  The maximum message size for messages sent from a device to the cloud is 256 KB. These messages are metered in 4 KB blocks for the paid tiers so for instance if the device sends a 16 KB message via the paid tiers it will be billed as 4 messages. The messages sent by devices connected via the free edition are metered in 0.5 KB blocks. For instance, if the device sends a 16 KB message via the IoT Hub free tier it will be billed as 32 messages.

  The maximum message size for message sent from the cloud to a device is 64 KB and is metered in 4-KB blocks for the paid tiers so, for instance, an 8-KB message sent via paid tiers would be billed as two messages. The messages sent using the free edition are metered in 0.5-KB blocks. For instance, an 8-KB message sent via the IoT Hub free tier will be billed as 16 messages.

• Is there a charge for messages related to File Upload?

  Only the messages which initiate a new upload and provide notification of a completed upload count against the daily allotment of messages. Customers must provide their own storage account and pay for storage. There is no separate charge for file upload. For example, in a typical file upload scenario, there are only two messages—the message that indicates that a file upload has been initiated, and the message that indicates that a file upload has been completed. Customers can choose to send additional data in the status description during notifications of a failed upload. Refer to the IoT Hub documentation for additional details about the file upload feature.

• What is the maximum size of file that I can send through the file upload feature?

  The file upload functionality of IoT Hub follows the upload limits that Azure Storage has in place.

• What are device twins, module twins and queries in the context of IoT Hub?

  Device twins contain device state information (metadata, configurations, and conditions) and are stored as JSON documents. Twins can be modified by your cloud and device applications, and support a rich query language. Device twins are the fundamental primitive of IoT Hub Device Management and can be accessed through several operations such as read, write, and queries. In addition, a device twin is shared between different device management components, basically with no isolation between components. With the introduction of module identity and module twin, an IoT developer can work separately without having others access his or her twin content. Each component on the device can work in isolation.

• How are twin reads, writes, and queries charged?

  Twin reads, writes, and queries are available only on standard tier are metered in 0.5-KB chunks with respect to the size of, respectively, the size of the returned twin, the size of update, and the size of query result. For instance, reading a 4-KB twin is billed as eight messages, updating a twin with a 1-KB payload is billed as two messages, querying twins for a 10-KB result is billed as 20 messages. All other messages are charged in chunks of 4-KB for the paid tiers (S1, S2, S3), and 0.5 KB for the free tier.

• How are direct methods charged?

  Direct methods is available only on standard tier and are request-response communications initiated by the cloud. The cloud receives an immediate response from the device. Both requests and responses can be at most 8 KB and are metered in 4-KB blocks for the paid tiers (i.e. S1, S2, and S3) so, for instance, an 8 KB request sent via the S1, S2, or S3 tiers would be billed as two messages. The requests sent using the free tier are metered in 0.5-KB blocks. For instance, an 8-KB message sent via the IoT Hub free tier will be billed as 16 messages.

• How are long running jobs charged?

  Jobs allow to start or schedule the execution of twin writes and direct methods on large sets of devices. Jobs operations are not billed, but the resulting twin writes and method invocations are billed as explained above.

• How does billing work for the IoT Hub service?

  The consumption of IoT Hub units is measured on a daily basis, and the billing is generated on a monthly basis. Customers are billed based on the number of IoT Hub units that have been consumed during the month.

• Is the billing prorated if I purchase an additional IoT Hub unit mid-month?

  You can choose to increase the number of IoT Hub units purchased at any time. If you sign up for the service mid-month, your monthly bill will be pro-rated based on the number of days remaining in the month. (For the purpose of the IoT Hub service, a month is defined as 31 days). If you increase the number of units of IoT Hub mid-month, your monthly bill will be based on the number of units available for each day during the month.

• Can I reduce the number of units if the business need changes?

  Yes, you can reduce the number of units from the Settings page at any point. The changes will take effect by the following day and be reflected on your bill at the end of the month.

• Can I switch from the Free Edition to one of the paid Editions?

  No, you cannot switch from Free to one of the paid editions. The free edition is meant to test out proof-of-concept solutions only.

• How do I cancel my IoT Hub service subscription?

  The IoT Hub subscription can be cancelled from the Azure Management Portal .

• What does device management in IoT Hub cost?

  Device management features are included as part of IoT Hub. Device management messages are measured like any other telemetry message in IoT Hub.

• How is IoT Hub Device Provisioning Service billed?

  IoT Hub Device Provisioning Service is billed by the number of operations. Operations include device registrations and re-registrations; operations also include service-side changes such as adding enrollment list entries, updating enrollment list entries and get/query operations. Every six months of inactivity on a given enrollment entry will incur a "keep-alive" operation.

• Can I switch among any of the Standard IoT Hub editions?

  Yes, you have to take the action of explicitly switching from one paid edition to another. The device identity and all messages are carried over to the new edition. If a customer wants to move from a higher tier to a lower tier, for instance from S2 to S1, and they have consumed more messages than S1 allows per day, then for that day the customer is billed at S2, and the customer is billed at the S1 rate starting the next day.

• Can I switch among any of the Basic IoT Hub editions?

  Yes, you have to take the action of explicitly switching from one paid edition to another. The device identity and all messages are carried over to the new edition. If a customer wants to move from a higher tier to a lower tier, for instance from B2 to B1, and they have consumed more messages than B1 allows per day, then for that day the customer is billed at B2, and the customer is billed at the B1 rate starting the next day.

• Can I switch from IoT Hub basic to standard tier and vice versa?

  Yes, you can upgrade from basic to standard tier via Azure Portal, but you cannot downgrade from standard to basic tier. To move from standard to basic you will have to create a new basic tier IoT Hub and need to re-register your devices to that IoT hub.