Overview

DMS for RocketMQ has two billing modes: yearly/monthly and pay-per-use.

Yearly/Monthly is a prepaid mode. You need to pay first, and will be billed for your subscription period. The longer the subscription, the bigger the discount. This mode is recommended for mature services that feature long-term stable requirements.
Pay-per-use is a postpaid mode. You can pay after using the service, and will be billed for your usage duration. The fees are calculated in seconds and settled by hour. This mode allows you to adjust resource usage easily. You do not need to prepare resources in advance, and will not have excessive or insufficient preset resources. This mode is recommended for scenarios such as e-commerce flash sales which feature sudden traffic bursts.

Table 1 compares the two billing modes.

**Table 1** Billing modes
Billing Mode	Yearly/Monthly	Pay-per-Use
Payment	Prepaid Billed by the required duration specified in your order	Postpaid Based on the usage duration of your RocketMQ instance.
Billing Period	Billed by the required duration specified in your order	Calculated in seconds, settled by hour.
Billing Items	Instance and storage space	Instance and storage space
Billing Mode Change	Can be changed to pay-per-use. The change takes effect only after the yearly/monthly subscription expires.	Can be changed to yearly/monthly.
Specification Change	Supported	Supported
Scenario	Recommended if you want a long-term use at low costs. Suitable for scenarios where resource usage periods can be estimated.	Recommended if you want more flexibility. Suitable for scenarios where resource demands fluctuate.