This topic describes the billing items and pricing of Message Queue for MQTT payasyougo instances.
Billing items
The following table lists the billing items of Message Queue for MQTT payasyougo instances.
Item  Definition  Description  Example 

Number of concurrent connections  The number of client connections over TCP on a single instance at any time. The number of concurrent connections is a transient value and is updated every minute.  The billing cycle is one day. The maximum number of concurrent connections within the 24 hours starting from 00:00 in the previous day is counted in each daily bill.  Assume that the number of concurrent connections of instance_a was 1,000 at 10:00 on August 8, 2017 and was 2,000 at 11:00 on August 8, 2017. In addition, the number did not reach 2,000 afterward on that day. The maximum number of concurrent connections of instance_a was 2,000 on August 8, 2017. Therefore, the number for which you were charged was 2,000. 
Number of sent and received messages  The maximum number of messages that are sent and received by using protocols supported by Message Queue for MQTT. 

Assume that instance_a has 100 clients and cleanSession is set to true for each client. Each client sends one QoS0 message, two QoS1 messages, and three QoS2 messages, and receives one QoS0 message, one QoS1 message, and one QoS2 message. The total number of sent and received message of instance_a is calculated in the following formula: 100 × (1 + 2 × 2 + 3 × 5) + 100 × (1 + 1 × 2 + 1 × 5) = 2,800. The number for which you are charged is 2,800. 
Number of subscriptions  The number of subscriptions that a user has registered with the Message Queue for MQTT broker.  The billing cycle is one day. The maximum number of subscriptions within the 24 hours starting from 00:00 in the previous day is counted in each daily bill.  Assume that the number of subscriptions of instance_a was 1,000 at 10:00 on August 8, 2017 and was 500 at 11:00 on August 8, 2017. In addition, the number did not reach 1,000 afterward on that day. The maximum number of subscriptions of instance_a was 1,000 on August 8, 2017. Therefore, the number for which you were charged was 1,000. 
Pricing
The following table lists the billing rules for the number of concurrent connections of Message Queue for MQTT payasyougo instances.
Number of concurrent connections  Price (USD) 

[1,100]  0.07 
> 100  Number of concurrent connections × 0.0007 
The following table lists the billing rules for the number of sent and received messages of Message Queue for MQTT payasyougo instances.
Number of sent and received messages (million)  Price (USD) 

> 0  Number of sent and received messages × 0.91 
The following table lists the billing rules for the number of subscriptions of Message Queue for MQTT payasyougo instances.
Number of subscriptions  Price (USD) 

[1,100]  0.01 
> 100  Number of subscriptions × 0.0001 