Edit

Durable Task Scheduler billing

The Durable Task Scheduler is a managed backend service that persists orchestration state. It's billed separately from the orchestration frameworks that connect to it. The Durable Task Scheduler doesn't charge for Durable Functions or the Durable Task SDKs directly. Your total cost has two components:

  • Durable Task Scheduler—billed based on the SKU you choose (Dedicated or Consumption)
  • Compute resources—billed separately by the platform hosting your application, whether that's Azure Functions (for Durable Functions) or a container/VM platform (for Durable Task SDKs)

The following table compares the two pricing models at a glance.

Dedicated Consumption
Billing model Fixed monthly cost per Capacity Unit (CU) Pay per action dispatched
Max throughput 2,000 actions/sec per CU (up to 3 CUs) 500 actions/sec
Data retention Up to 90 days Up to 30 days
High availability Supported (requires 3 CUs) Not available
Best for Production workloads with predictable volume Dev/test and variable workloads

For current pricing, see the Durable Task Scheduler pricing page.

What is an action?

An action is a message dispatched by the Durable Task Scheduler to your application, triggering the execution of an orchestrator, activity, or entity function. Actions include:

  • Starting an orchestration or suborchestration
  • Starting an activity
  • Completing a timer
  • Triggering an external event
  • Executing an entity operation
  • Pausing, resuming, or terminating an orchestration
  • Processing the result of an activity, entity call, entity lock, or suborchestration

The following diagram shows how to calculate actions in your orchestration.

Diagram showing how to calculate the number of billing actions in a Durable Task Scheduler orchestration.

Example

An orchestration that calls three different activities incurs the following actions:

Screenshot of Durable Task Scheduler orchestration code showing three activity function calls and their corresponding action breakdown.

In this example, Durable Task Scheduler processes each action as shown here:

  • Orchestrator start (RunOrchestrator) uses one action
  • Activity 1 ((nameof(SayHello), "Tokyo")) uses two actions:
    • Scheduling the activity
    • Processing the result
  • Activity 2 ((nameof(SayHello), "Seattle")) uses two actions:
    • Scheduling the activity
    • Processing the result
  • Activity 3 ((nameof(SayHello), "London")) uses two actions:
    • Scheduling the activity
    • Processing the result

Dedicated SKU pricing and capacity

The Dedicated SKU provides predictable performance through preallocated Capacity Units (CUs). Each deployment supports up to three CUs. You can create up to 25 schedulers and 25 task hubs per region per subscription with the Dedicated SKU. For more quota, contact support.

Key features

Feature Description
Base cost Fixed monthly cost per CU (regional pricing). Not "per action" billing.
Performance Each CU supports up to 2,000 actions per second and 50 GB of orchestration data storage.
Orchestration data retention Up to 90 days.
Custom scaling Configure CUs to match your workload needs. One CU required per deployment.
High availability High availability with multi-CU deployments. A minimum of three CUs is required.

Note

For high-availability deployments, configure three CUs. Single-CU deployments don't provide redundancy.

Calculate capacity units for the Dedicated SKU

Example 1

You have an orchestration with five activities, plus error handling, and averaging 12 actions per orchestration (orchestrator and activity invocations). Let's calculate running 20 million orchestrations per month.

Step Calculation Result
Monthly actions 20,000,000 × 12 240,000,000 actions
Actions per second 240,000,000 ÷ 2,628,000 (seconds in a month) ≈ 91 actions/second
Required CUs 91 ÷ 2,000 CUs needed: 0.046 → 1 CU sufficient

Example 2

A large enterprise runs 500 million complex orchestrations monthly, with an average of 15 actions per orchestration (multiple activities with orchestrator coordination).

Step Calculation Result
Monthly actions 500 million × 15 7.5 billion actions
Actions per second 7.5 billion ÷ 2,628,000 ≈ 2,854 actions/second
Required CUs 2,854 ÷ 2,000 CUs needed: 1.43 → 2 CUs sufficient

Example 3

A software as a service (SaaS) platform supports 800 million orchestrations monthly, each with an average of 15 actions (user interactions, background processing, and external API calls).

Step Calculation Result
Monthly actions 800 million × 15 12 billion actions
Actions per second 12 billion ÷ 2,628,000 ≈ 4,571 actions/second
Required CUs 4,571 ÷ 2,000 CUs needed: 2.29 → 3 CUs sufficient

Consumption SKU

The Consumption SKU offers a pay-as-you-use model, ideal for variable workloads and development scenarios.

You can create up to 10 schedulers and 5 task hubs per region per subscription with the Consumption SKU. For more quota, contact support.

Key features

Feature Description
Pay-per-use Pay only for actions dispatched. No upfront costs, minimum commitments, or base fees.
Performance Supports up to 500 actions per second.
Data retention Retains data for a maximum of 30 days.

Example 1

A development team is testing simple orchestrations, each with three actions (using the "Hello City" pattern), and runs 10,000 orchestrations per month.

Step Calculation Result
Monthly actions 10,000 × 3 30,000 actions

Example 2

An e-commerce application experiences dynamic scaling during promotional sales events. It uses an orchestration that has seven total actions, which runs approximately 20,000 times per month.

Step Calculation Result
Monthly actions 20,000 × 7 140,000 actions

Compute costs

In addition to the Durable Task Scheduler, you pay for the compute platform that hosts your application. Your compute costs depend on the orchestration framework you use.

Durable Functions

Durable Functions runs on Azure Functions. Your compute costs depend on the Azure Functions hosting plan you choose:

Hosting plan Description
Consumption plan Pay only for the time your functions run. Includes automatic scaling and a free monthly grant.
Flex Consumption plan Event-driven scaling with virtual network integration. Pay for instances during request processing, plus an always-ready baseline.
Premium plan Prewarmed instances to avoid cold starts, with virtual network connectivity. Billed per vCPU and memory second.
Dedicated (App Service) plan Run functions on dedicated virtual machines within an App Service plan. Best when you have underused VMs that already run other App Service instances.

For detailed Durable Functions billing behaviors (replay billing, awaiting, HTTP polling), see Durable Functions billing. For Azure Functions pricing, see Azure Functions pricing.

Durable Task SDKs

The Durable Task SDKs are platform-agnostic and can run on different compute platforms:

Compute platform Description
Azure Container Apps Serverless container hosting with consumption-based or dedicated pricing. Billed for vCPU and memory usage.
Azure Kubernetes Service (AKS) Managed Kubernetes clusters where you pay for the virtual machines (nodes) in your cluster.
Azure App Service Fully managed platform for hosting web applications with different pricing tiers based on features and scale.

For detailed pricing information, see the billing documentation for each compute service:

Related content

  • Last updated on