Standalone Activities - .NET SDK

SUPPORT, STABILITY, and DEPENDENCY INFO

Temporal .NET SDK support for Standalone Activities is at Pre-release.

All APIs are experimental and may be subject to backwards-incompatible changes.

Standalone Activities are Activities that run independently, without being orchestrated by a Workflow. Instead of starting an Activity from within a Workflow Definition, you start a Standalone Activity directly from a Temporal Client.

The way you write the Activity and register it with a Worker is identical to Workflow Activities. The only difference is that you execute a Standalone Activity directly from your Temporal Client.

This page covers the following:

• Get Started with Standalone Activities
• Define your Activity
• Run a Worker with the Activity registered
• Execute a Standalone Activity
• Start a Standalone Activity without waiting for the result
• Get a handle to an existing Standalone Activity
• Wait for the result of a Standalone Activity
• List Standalone Activities
• Count Standalone Activities
• Run Standalone Activities with Temporal Cloud

note

This documentation uses source code from the StandaloneActivity sample project.

Get Started with Standalone Activities

Prerequisites:

• .NET 8.0+

• Temporal .NET SDK (v1.12.0 or higher). See the .NET Quickstart for install instructions.

• Temporal CLI (Pre-release version with Standalone Activity support)

  Download for your platform:

  macOS (Apple Silicon)

  curl -L https://github.com/temporalio/cli/releases/download/v1.6.2-standalone-activity/temporal_cli_1.6.2-standalone-activity_darwin_arm64.tar.gz | tar xz

  macOS (Intel)

  curl -L https://github.com/temporalio/cli/releases/download/v1.6.2-standalone-activity/temporal_cli_1.6.2-standalone-activity_darwin_amd64.tar.gz | tar xz

  Linux (arm64)

  curl -L https://github.com/temporalio/cli/releases/download/v1.6.2-standalone-activity/temporal_cli_1.6.2-standalone-activity_linux_arm64.tar.gz | tar xz

  Linux (amd64)

  curl -L https://github.com/temporalio/cli/releases/download/v1.6.2-standalone-activity/temporal_cli_1.6.2-standalone-activity_linux_amd64.tar.gz | tar xz

  Verify the installation:

  ./temporal --version
  # temporal version 1.6.2-standalone-activity (Server 1.31.0-151.2, UI 2.47.2)

  Move the binary to your PATH or run it from the current directory as ./temporal.

  danger

  If you see Standalone activity is disabled when running commands, you are using the standard Temporal CLI instead of the pre-release version above. The standard brew install temporal or brew upgrade temporal does not include Standalone Activity support during Pre-release.

Start the Temporal development server:

./temporal server start-dev

This command automatically starts the Temporal development server with the Web UI, and creates the default Namespace. It uses an in-memory database, so do not use it for real use cases.

Temporal Cloud

All code samples on this page use ClientEnvConfig.LoadClientConnectOptions() to configure the Temporal Client connection. It responds to environment variables and TOML configuration files, so the same code works against a local dev server and Temporal Cloud without changes. See Run Standalone Activities with Temporal Cloud below.

The Temporal Server will now be available for client connections on localhost:7233, and the Temporal Web UI will now be accessible at http://localhost:8233. Standalone Activities are available from the nav bar item located towards the top left of the page:

Clone the samples-dotnet repository to follow along:

git clone https://github.com/temporalio/samples-dotnet.git
cd samples-dotnet

The sample project is structured as follows:

src/StandaloneActivity/
├── MyActivities.cs
├── Program.cs
├── README.md
└── TemporalioSamples.StandaloneActivity.csproj

Define your Activity

An Activity in the Temporal .NET SDK is a method decorated with the [Activity] attribute. The way you write a Standalone Activity is identical to how you write an Activity orchestrated by a Workflow. In fact, the same Activity can be executed both as a Standalone Activity and as a Workflow Activity.

src/StandaloneActivity/MyActivities.cs

namespace TemporalioSamples.StandaloneActivity;

using Temporalio.Activities;

public static class MyActivities
{
    [Activity]
    public static Task<string> ComposeGreetingAsync(ComposeGreetingInput input) =>
        Task.FromResult($"{input.Greeting}, {input.Name}!");
}

public record ComposeGreetingInput(string Greeting, string Name);

Run a Worker with the Activity registered

Running a Worker for Standalone Activities is the same as running a Worker for Workflow Activities — you create a Worker, register the Activity, and run the Worker. The Worker doesn't need to know whether the Activity will be invoked from a Workflow or as a Standalone Activity. See How to develop a Worker for more details on Worker setup and configuration options.

src/StandaloneActivity/Program.cs

using Microsoft.Extensions.Logging;
using Temporalio.Client;
using Temporalio.Common.EnvConfig;
using Temporalio.Worker;
using TemporalioSamples.StandaloneActivity;

var connectOptions = ClientEnvConfig.LoadClientConnectOptions();
connectOptions.TargetHost ??= "localhost:7233";
connectOptions.LoggerFactory = LoggerFactory.Create(builder =>
    builder.
        AddSimpleConsole(options => options.TimestampFormat = "[HH:mm:ss] ").
        SetMinimumLevel(LogLevel.Information));
var client = await TemporalClient.ConnectAsync(connectOptions);

const string taskQueue = "standalone-activity-sample";

using var tokenSource = new CancellationTokenSource();
Console.CancelKeyPress += (_, eventArgs) =>
{
    tokenSource.Cancel();
    eventArgs.Cancel = true;
};

using var worker = new TemporalWorker(
    client,
    new TemporalWorkerOptions(taskQueue).
        AddActivity(MyActivities.ComposeGreetingAsync));

await worker.ExecuteAsync(tokenSource.Token);

Open a new terminal, navigate to the samples-dotnet directory, and run the Worker:

dotnet run --project src/StandaloneActivity worker

Leave this terminal running - the Worker needs to stay up to process activities.

Execute a Standalone Activity

Use client.ExecuteActivityAsync() to execute a Standalone Activity and wait for the result. Call this from your application code, not from inside a Workflow Definition. This durably enqueues your Standalone Activity in the Temporal Server, waits for it to be executed on your Worker, and then returns the result.

src/StandaloneActivity/Program.cs

using Temporalio.Client;
using Temporalio.Common.EnvConfig;
using TemporalioSamples.StandaloneActivity;

var connectOptions = ClientEnvConfig.LoadClientConnectOptions();
connectOptions.TargetHost ??= "localhost:7233";
var client = await TemporalClient.ConnectAsync(connectOptions);

var result = await client.ExecuteActivityAsync(
    () => MyActivities.ComposeGreetingAsync(new ComposeGreetingInput("Hello", "World")),
    new("standalone-activity-id", "standalone-activity-sample")
    {
        ScheduleToCloseTimeout = TimeSpan.FromSeconds(10),
    });
Console.WriteLine($"Activity result: {result}");

You can pass the Activity as either a lambda expression or a string Activity type name:

// Using a lambda expression (type-safe)
var result = await client.ExecuteActivityAsync(
    () => MyActivities.ComposeGreetingAsync(new ComposeGreetingInput("Hello", "World")),
    new("my-activity-id", "my-task-queue")
    {
        ScheduleToCloseTimeout = TimeSpan.FromSeconds(10),
    });

// Using a string type name
var result = await client.ExecuteActivityAsync<string>(
    "ComposeGreeting",
    new object?[] { new ComposeGreetingInput("Hello", "World") },
    new("my-activity-id", "my-task-queue")
    {
        ScheduleToCloseTimeout = TimeSpan.FromSeconds(10),
    });

StartActivityOptions requires Id, TaskQueue, and at least one of ScheduleToCloseTimeout or StartToCloseTimeout. See StartActivityOptions in the API reference for the full set of options.

To run it:

1. Make sure the Temporal Server is running (from the Get Started step above).
2. Make sure the Worker is running (from the Run a Worker step above).
3. Open a new terminal, navigate to the samples-dotnet directory, and run:

dotnet run --project src/StandaloneActivity execute-activity

Or use the Temporal CLI:

./temporal activity execute \
  --type ComposeGreeting \
  --activity-id standalone-activity-id \
  --task-queue standalone-activity-sample \
  --schedule-to-close-timeout 10s \
  --input '{"Greeting": "Hello", "Name": "World"}'

Start a Standalone Activity without waiting for the result

Use client.StartActivityAsync() to start a Standalone Activity and get a handle without waiting for the result:

src/StandaloneActivity/Program.cs

using Temporalio.Client;
using Temporalio.Common.EnvConfig;
using TemporalioSamples.StandaloneActivity;

var connectOptions = ClientEnvConfig.LoadClientConnectOptions();
connectOptions.TargetHost ??= "localhost:7233";
var client = await TemporalClient.ConnectAsync(connectOptions);

var handle = await client.StartActivityAsync(
    () => MyActivities.ComposeGreetingAsync(new ComposeGreetingInput("Hello", "World")),
    new("standalone-activity-id", "standalone-activity-sample")
    {
        ScheduleToCloseTimeout = TimeSpan.FromSeconds(10),
    });
Console.WriteLine($"Started activity: {handle.Id}");

// Wait for the result later
var result = await handle.GetResultAsync();
Console.WriteLine($"Activity result: {result}");

With the Temporal Server and Worker running, open a new terminal in the samples-dotnet directory and run:

dotnet run --project src/StandaloneActivity start-activity

Or use the Temporal CLI:

./temporal activity start \
  --type ComposeGreeting \
  --activity-id standalone-activity-id \
  --task-queue standalone-activity-sample \
  --schedule-to-close-timeout 10s \
  --input '{"Greeting": "Hello", "Name": "World"}'

Get a handle to an existing Standalone Activity

Use client.GetActivityHandle() to create a handle to a previously started Standalone Activity:

// Without a known result type
var handle = client.GetActivityHandle("my-activity-id", runId: "the-run-id");

// With a known result type
var typedHandle = client.GetActivityHandle<string>("my-activity-id", runId: "the-run-id");

You can use the handle to wait for the result, describe, cancel, or terminate the Activity.

Wait for the result of a Standalone Activity

Under the hood, calling client.ExecuteActivityAsync() is the same as calling client.StartActivityAsync() to durably enqueue the Standalone Activity, and then calling await handle.GetResultAsync() to wait for the Activity to be executed and return the result:

var result = await handle.GetResultAsync();

Or use the Temporal CLI to wait for a result by Activity ID:

./temporal activity result --activity-id my-standalone-activity-id

List Standalone Activities

Use client.ListActivitiesAsync() to list Standalone Activity Executions that match a List Filter query. The result is an IAsyncEnumerable that yields ActivityExecution entries.

These APIs return only Standalone Activity Executions. Activities running inside Workflows are not included.

src/StandaloneActivity/Program.cs

using Temporalio.Client;
using Temporalio.Common.EnvConfig;

var connectOptions = ClientEnvConfig.LoadClientConnectOptions();
connectOptions.TargetHost ??= "localhost:7233";
var client = await TemporalClient.ConnectAsync(connectOptions);

await foreach (var info in client.ListActivitiesAsync(
    "TaskQueue = 'standalone-activity-sample'"))
{
    Console.WriteLine(
        $"ActivityID: {info.ActivityId}, Type: {info.ActivityType}, Status: {info.Status}");
}

Run it:

dotnet run --project src/StandaloneActivity list-activities

Or use the Temporal CLI:

./temporal activity list

The query parameter accepts the same List Filter syntax used for Workflow Visibility. For example, "ActivityType = 'ComposeGreeting' AND Status = 'Running'".

Count Standalone Activities

Use client.CountActivitiesAsync() to count Standalone Activity Executions that match a List Filter query. This returns the total count of executions (running, completed, failed, etc.) - not the number of queued tasks. It works the same way as counting Workflow Executions.

src/StandaloneActivity/Program.cs

using Temporalio.Client;
using Temporalio.Common.EnvConfig;

var connectOptions = ClientEnvConfig.LoadClientConnectOptions();
connectOptions.TargetHost ??= "localhost:7233";
var client = await TemporalClient.ConnectAsync(connectOptions);

var resp = await client.CountActivitiesAsync(
    "TaskQueue = 'standalone-activity-sample'");
Console.WriteLine($"Total activities: {resp.Count}");

Run it:

dotnet run --project src/StandaloneActivity count-activities

Or use the Temporal CLI:

./temporal activity count

Run Standalone Activities with Temporal Cloud

The code samples on this page use ClientEnvConfig.LoadClientConnectOptions(), so the same code works against Temporal Cloud - just configure the connection via environment variables or a TOML profile. No code changes are needed.

For a step-by-step guide on connecting to Temporal Cloud, including Namespace creation, certificate generation, and authentication setup in the Cloud UI, see Connect to Temporal Cloud.

Connect with mTLS

Set these environment variables with values from your Temporal Cloud Namespace settings:

export TEMPORAL_ADDRESS=<your-namespace>.<your-account-id>.tmprl.cloud:7233
export TEMPORAL_NAMESPACE=<your-namespace>.<your-account-id>
export TEMPORAL_TLS_CLIENT_CERT_PATH='path/to/your/client.pem'
export TEMPORAL_TLS_CLIENT_KEY_PATH='path/to/your/client.key'

Connect with an API key

Set these environment variables with values from your Temporal Cloud API key settings:

export TEMPORAL_ADDRESS=<region>.<cloud_provider>.api.temporal.io:7233
export TEMPORAL_NAMESPACE=<your-namespace>.<your-account-id>
export TEMPORAL_API_KEY=<your-api-key>

Then run the Worker and starter code as shown in the earlier sections.