diff --git a/src/clients/Elsa.Api.Client/Extensions/DependencyInjectionExtensions.cs b/src/clients/Elsa.Api.Client/Extensions/DependencyInjectionExtensions.cs
index 4bc70d80c..f846e499e 100644
--- a/src/clients/Elsa.Api.Client/Extensions/DependencyInjectionExtensions.cs
+++ b/src/clients/Elsa.Api.Client/Extensions/DependencyInjectionExtensions.cs
@@ -12,6 +12,7 @@ using Elsa.Api.Client.Resources.Resilience.Contracts;
 using Elsa.Api.Client.Resources.Scripting.Contracts;
 using Elsa.Api.Client.Resources.StorageDrivers.Contracts;
 using Elsa.Api.Client.Resources.Tasks.Contracts;
+using Elsa.Api.Client.Resources.Tests;
 using Elsa.Api.Client.Resources.VariableTypes.Contracts;
 using Elsa.Api.Client.Resources.WorkflowActivationStrategies.Contracts;
 using Elsa.Api.Client.Resources.WorkflowDefinitions.Contracts;
@@ -86,6 +87,7 @@ public static class DependencyInjectionExtensions
             services.AddApi<IWorkflowContextProviderDescriptorsApi>(builderOptions);
             services.AddApi<IAlterationsApi>(builderOptions);
             services.AddApi<ITasksApi>(builderOptions);
+            services.AddApi<ITestsApi>(builderOptions);
         });
     }
 
diff --git a/src/clients/Elsa.Api.Client/Resources/Tests/ITestsApi.cs b/src/clients/Elsa.Api.Client/Resources/Tests/ITestsApi.cs
new file mode 100644
index 000000000..09748d7e1
--- /dev/null
+++ b/src/clients/Elsa.Api.Client/Resources/Tests/ITestsApi.cs
@@ -0,0 +1,18 @@
+using Refit;
+
+namespace Elsa.Api.Client.Resources.Tests;
+
+/// <summary>
+/// Represents a client for the testing API.
+/// </summary>
+public interface ITestsApi
+{
+    /// <summary>
+    /// Sends the specified request to the login API.
+    /// </summary>
+    /// <param name="request">The request.</param>
+    /// <param name="cancellationToken">The cancellation token.</param>
+    /// <returns>The response.</returns>
+    [Post("/tests/activities")]
+    Task<TestActivityResponse> TestActivityAsync([Body] TestActivityRequest request, CancellationToken cancellationToken = default);
+}
\ No newline at end of file
diff --git a/src/clients/Elsa.Api.Client/Resources/Tests/TestActivityRequest.cs b/src/clients/Elsa.Api.Client/Resources/Tests/TestActivityRequest.cs
new file mode 100644
index 000000000..49dfe56d0
--- /dev/null
+++ b/src/clients/Elsa.Api.Client/Resources/Tests/TestActivityRequest.cs
@@ -0,0 +1,9 @@
+using Elsa.Api.Client.Resources.WorkflowDefinitions.Models;
+
+namespace Elsa.Api.Client.Resources.Tests;
+
+public class TestActivityRequest
+{
+    public WorkflowDefinitionHandle WorkflowDefinitionHandle { get; set; } = null!;
+    public ActivityHandle ActivityHandle { get; set; } = null!;
+}
\ No newline at end of file
diff --git a/src/clients/Elsa.Api.Client/Resources/Tests/TestActivityResponse.cs b/src/clients/Elsa.Api.Client/Resources/Tests/TestActivityResponse.cs
new file mode 100644
index 000000000..2830e7431
--- /dev/null
+++ b/src/clients/Elsa.Api.Client/Resources/Tests/TestActivityResponse.cs
@@ -0,0 +1,12 @@
+using Elsa.Api.Client.Resources.WorkflowInstances.Models;
+using Elsa.Api.Client.Shared.Models;
+
+namespace Elsa.Api.Client.Resources.Tests;
+
+public class TestActivityResponse
+{
+    public IDictionary<string, object?>? Outputs { get; set; }
+    public ICollection<string>? Outcomes { get; set; }
+    public ExceptionState? Exception { get; set; }
+    public ActivityStatus Status { get; set; }
+}
\ No newline at end of file
diff --git a/src/clients/Elsa.Api.Client/Resources/WorkflowDefinitions/Models/ActivityHandle.cs b/src/clients/Elsa.Api.Client/Resources/WorkflowDefinitions/Models/ActivityHandle.cs
new file mode 100644
index 000000000..c6ee9fd16
--- /dev/null
+++ b/src/clients/Elsa.Api.Client/Resources/WorkflowDefinitions/Models/ActivityHandle.cs
@@ -0,0 +1,16 @@
+namespace Elsa.Api.Client.Resources.WorkflowDefinitions.Models;
+
+/// <summary>
+/// Represents a handle to an activity.
+/// </summary>
+public class ActivityHandle
+{
+    public static ActivityHandle FromActivityId(string activityId) => new() { ActivityId = activityId };
+    public static ActivityHandle FromActivityNodeId(string activityNodeId) => new() { ActivityNodeId = activityNodeId };
+    public static ActivityHandle FromActivityInstanceId(string activityInstanceId) => new() { ActivityInstanceId = activityInstanceId };
+    public static ActivityHandle FromActivityHash(string activityHash) => new() { ActivityHash = activityHash };
+    public string? ActivityId { get; init; }
+    public string? ActivityNodeId { get; init;}
+    public string? ActivityInstanceId { get; init;}
+    public string? ActivityHash { get; init;}
+}
\ No newline at end of file
diff --git a/src/clients/Elsa.Api.Client/Resources/WorkflowDefinitions/Models/WorkflowDefinitionHandle.cs b/src/clients/Elsa.Api.Client/Resources/WorkflowDefinitions/Models/WorkflowDefinitionHandle.cs
new file mode 100644
index 000000000..1cbc95abc
--- /dev/null
+++ b/src/clients/Elsa.Api.Client/Resources/WorkflowDefinitions/Models/WorkflowDefinitionHandle.cs
@@ -0,0 +1,48 @@
+using Elsa.Api.Client.Shared.Models;
+
+namespace Elsa.Api.Client.Resources.WorkflowDefinitions.Models;
+
+/// <summary>
+/// Represents a handle to a workflow definition.
+/// </summary>
+public class WorkflowDefinitionHandle
+{
+    /// <summary>
+    /// Gets or sets the definition ID. When set, the <see cref="DefinitionVersionId"/> property is ignored.
+    /// </summary>
+    public string? DefinitionId { get; set; }
+    
+    /// <summary>
+    /// Gets or sets the version options. When set, the <see cref="DefinitionVersionId"/> property is ignored.
+    /// </summary>
+    public VersionOptions? VersionOptions { get; set; }
+
+    /// <summary>
+    /// Gets or sets the definition version ID. When set, the <see cref="DefinitionId"/> and <see cref="VersionOptions"/> properties are ignored.
+    /// </summary>
+    public string? DefinitionVersionId { get; set; }
+    
+    /// <summary>
+    /// Creates a new <see cref="WorkflowDefinitionHandle"/> instance with the specified definition ID and version options.
+    /// </summary>
+    public static WorkflowDefinitionHandle ByDefinitionId(string definitionId, VersionOptions? versionOptions = null) => new() { DefinitionId = definitionId, VersionOptions = versionOptions };
+    
+    /// <summary>
+    /// Creates a new <see cref="WorkflowDefinitionHandle"/> instance with the specified definition version ID.
+    /// </summary>
+    /// <param name="definitionVersionId"></param>
+    /// <returns></returns>
+    public static WorkflowDefinitionHandle ByDefinitionVersionId(string definitionVersionId) => new() { DefinitionVersionId = definitionVersionId };
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        if (DefinitionId != null)
+            return $"DefinitionId: {DefinitionId}, VersionOptions: {VersionOptions}";
+        
+        if (DefinitionVersionId != null)
+            return $"DefinitionVersionId: {DefinitionVersionId}";
+
+        return string.Empty;
+    }
+}
\ No newline at end of file