This topic describes the specifications, free monthly quota, usage modes, billable items, and unit prices of flexible instances in Function Compute.

Instance specifications

Memory size (MB) Maximum package size (MB) Maximum execution duration of functions (s) Disk size (MB)
128~3072 50 900 512

Free monthly quota

Function Compute provides you with the free monthly quota. Your Alibaba Cloud account and RAM users share the free monthly quota of requests and execution duration of functions. The free monthly quota does not accumulate. At 00:00:00 on the first day of each calendar month, the free quota is cleared and recalculated. The following resources are included in the free monthly quota:

Notice The free monthly quota can be used only for pay-as-you-go flexible instances.
  • Requests: The first one million requests each month are free of charge.
  • Resources for function executions: The first 400,000 GB-s of resources used by instances each month are free of charge.

Usage modes

For more information about the usage modes of flexible instances, see Instance specifications and usage modes.

Billable items and unit prices

Function invocation fees = Number of requests x Unit price
Unit price: USD 0.2 per 1,000,000 requests
Fees for resource usage of instances = Computing power of instances × Execution duration × Unit price
  • Computing power of instances: The computing power of an instance is proportional to the memory size allocated to the instance. To simplify the billing model, Function Compute uses the memory size of an instance to indicate the computing power of the instance.
  • Execution duration: Instances can be used in provisioned or on-demand mode. The execution duration of functions by provisioned instances and that by on-demand instances are measured in different ways.
    • On-demand mode: The billing granularity is 1 millisecond.
    • Provisioned mode: The billing granularity is 1 second. If the execution duration is less than 1 minute, it is billed as 1 minute. For example, if the execution duration of functions by a provisioned flexible instance is 51 seconds, the execution duration is billed as 1 minute. If the execution duration is 61 seconds, it is billed as 61 seconds.

    For more information, see Instance specifications and usage modes.

  • Function Compute provides computing capabilities that match those of Elastic Compute Service (ECS) and Container Service for Kubernetes. You do not need to worry about the computing power of instances.
  • Function Compute allows you to concurrently process requests by using a single instance. Reused resources are billed based on the amount of resources that are used and are not repeatedly billed for each reuse.
Unit prices
The resource usage of instances is billed in the following two methods:
  • Subscription: Purchase a specific number of resource coupons based on the estimated requirements before you use Function Compute.
    Unit price: USD 12.16 per GB per month. This is the monthly fee for an instance that has 1 GB of computing power.
  • Pay-as-you-go: Pay for the resources that are used.
    Unit price: USD 0.000016384 per GB per second. This is the fee for an instance that has 1 GB of computing power to execute requests for 1 second.

  • When you purchase resource coupons, no instances are created.
  • Resource coupons can be used to offset the fees for both provisioned and on-demand instances. If Function Compute fails to deliver the resources that you purchased due to insufficient underlying computing resources, you can be reimbursed for the fees for the undelivered resources. We recommend that you create provisioned instances and purchase resource coupons to offset the fees for the instances.
  • For more information about how to minimize the costs in subscription mode, see Best practices of minimizing Function Compute costs.
Fees for outbound Internet traffic = Traffic within a function × Traffic unit price + Traffic for responses to requests × Traffic unit price + CDN back-to-origin traffic × Traffic unit price
  • Traffic within a function: the traffic generated when the function sends requests to the Internet.
    Unit price: USD 0.117 per GB
  • Traffic for responses to requests: the traffic generated when the function sends responses to requests.
    Unit price: USD 0.117 per GB
  • CDN back-to-origin traffic: the traffic generated when the function is used as the origin of Alibaba Cloud CDN.
    Unit price: USD 0.117 per GB

  • Traffic over the internal network is free of charge.
  • Inbound Internet traffic is free of charge. For example, you are not charged when functions in Function Compute read or download files from the Internet. However, you are charged for the traffic generated when functions write files to storage objects on the Internet.
If you use other Alibaba Cloud services together with your functions, additional fees are charged for these services. For example, if you use a function to write data to Object Storage Service (OSS) or activate Log Service to store the logs of your functions, additional fees for OSS or Log Service are charged.