diff --git a/test/Core.Test/Models/Api/Request/PushSendRequestModelTests.cs b/test/Core.Test/Models/Api/Request/PushSendRequestModelTests.cs
new file mode 100644
index 000000000000..4163d32028f9
--- /dev/null
+++ b/test/Core.Test/Models/Api/Request/PushSendRequestModelTests.cs
@@ -0,0 +1,76 @@
+#nullable enable
+using System.ComponentModel.DataAnnotations;
+using Bit.Core.Enums;
+using Bit.Core.Models.Api;
+using Xunit;
+
+namespace Bit.Core.Test.Models.Api.Request;
+
+public class PushSendRequestModelTests
+{
+    [Theory]
+    [InlineData(null, null)]
+    [InlineData(null, "")]
+    [InlineData(null, " ")]
+    [InlineData("", null)]
+    [InlineData(" ", null)]
+    [InlineData("", "")]
+    [InlineData(" ", " ")]
+    public void Validate_UserIdOrganizationIdNullOrEmpty_Invalid(string? userId, string? organizationId)
+    {
+        var model = new PushSendRequestModel
+        {
+            UserId = userId,
+            OrganizationId = organizationId,
+            Type = PushType.SyncCiphers,
+            Payload = "test"
+        };
+
+        var results = Validate(model);
+
+        Assert.Single(results);
+        Assert.Contains(results, result => result.ErrorMessage == "UserId or OrganizationId is required.");
+    }
+
+    [Fact]
+    public void Validate_RequiredPayloadFieldNotProvided_Invalid()
+    {
+        var model = new PushSendRequestModel
+        {
+            UserId = Guid.NewGuid().ToString(),
+            OrganizationId = Guid.NewGuid().ToString(),
+            Type = PushType.SyncCiphers
+        };
+
+        var results = Validate(model);
+
+        Assert.Single(results);
+        Assert.Contains(results, result => result.ErrorMessage == "The Payload field is required.");
+    }
+
+    [Fact]
+    public void Validate_AllFieldsPresent_Valid()
+    {
+        var model = new PushSendRequestModel
+        {
+            UserId = Guid.NewGuid().ToString(),
+            OrganizationId = Guid.NewGuid().ToString(),
+            Type = PushType.SyncCiphers,
+            Payload = "test payload",
+            Identifier = Guid.NewGuid().ToString(),
+            ClientType = ClientType.All,
+            DeviceId = Guid.NewGuid().ToString()
+        };
+
+        var results = Validate(model);
+
+        Assert.Empty(results);
+    }
+
+    private static List<ValidationResult> Validate(PushSendRequestModel model)
+    {
+        var results = new List<ValidationResult>();
+        Validator.TryValidateObject(model, new ValidationContext(model), results);
+        return results;
+    }
+}
diff --git a/test/Core.Test/NotificationHub/NotificationHubPushNotificationServiceTests.cs b/test/Core.Test/NotificationHub/NotificationHubPushNotificationServiceTests.cs
index ea9ce54131e8..4a20f517299f 100644
--- a/test/Core.Test/NotificationHub/NotificationHubPushNotificationServiceTests.cs
+++ b/test/Core.Test/NotificationHub/NotificationHubPushNotificationServiceTests.cs
@@ -1,42 +1,163 @@
-using Bit.Core.NotificationHub;
+using System.Text.Json;
+using Bit.Core.Enums;
+using Bit.Core.Models;
+using Bit.Core.Models.Data;
+using Bit.Core.NotificationCenter.Entities;
+using Bit.Core.NotificationHub;
 using Bit.Core.Repositories;
-using Bit.Core.Services;
-using Microsoft.AspNetCore.Http;
-using Microsoft.Extensions.Logging;
+using Bit.Core.Test.NotificationCenter.AutoFixture;
+using Bit.Test.Common.AutoFixture;
+using Bit.Test.Common.AutoFixture.Attributes;
 using NSubstitute;
 using Xunit;
 
 namespace Bit.Core.Test.NotificationHub;
 
+[SutProviderCustomize]
 public class NotificationHubPushNotificationServiceTests
 {
-    private readonly NotificationHubPushNotificationService _sut;
+    [Theory]
+    [BitAutoData]
+    [NotificationCustomize]
+    public async void PushSyncNotificationAsync_Global_NotSent(
+        SutProvider<NotificationHubPushNotificationService> sutProvider, Notification notification)
+    {
+        await sutProvider.Sut.PushSyncNotificationAsync(notification);
+
+        await sutProvider.GetDependency<INotificationHubPool>()
+            .Received(0)
+            .AllClients
+            .Received(0)
+            .SendTemplateNotificationAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<string>());
+        await sutProvider.GetDependency<IInstallationDeviceRepository>()
+            .Received(0)
+            .UpsertAsync(Arg.Any<InstallationDeviceEntity>());
+    }
+
+    [Theory]
+    [BitAutoData(false)]
+    [BitAutoData(true)]
+    [NotificationCustomize(false)]
+    public async void PushSyncNotificationAsync_UserIdProvidedClientTypeAll_SentToUser(
+        bool organizationIdNull, SutProvider<NotificationHubPushNotificationService> sutProvider,
+        Notification notification)
+    {
+        if (organizationIdNull)
+        {
+            notification.OrganizationId = null;
+        }
+
+        notification.ClientType = ClientType.All;
+        var expectedSyncNotification = ToSyncNotificationPushNotification(notification);
+
+        await sutProvider.Sut.PushSyncNotificationAsync(notification);
+
+        await AssertSendTemplateNotificationAsync(sutProvider, PushType.SyncNotification, expectedSyncNotification,
+            $"(template:payload_userId:{notification.UserId})");
+        await sutProvider.GetDependency<IInstallationDeviceRepository>()
+            .Received(0)
+            .UpsertAsync(Arg.Any<InstallationDeviceEntity>());
+    }
+
+    [Theory]
+    [BitAutoData(false, ClientType.Browser)]
+    [BitAutoData(false, ClientType.Desktop)]
+    [BitAutoData(false, ClientType.Web)]
+    [BitAutoData(false, ClientType.Mobile)]
+    [BitAutoData(true, ClientType.Browser)]
+    [BitAutoData(true, ClientType.Desktop)]
+    [BitAutoData(true, ClientType.Web)]
+    [BitAutoData(true, ClientType.Mobile)]
+    [NotificationCustomize(false)]
+    public async void PushSyncNotificationAsync_UserIdProvidedClientTypeNotAll_SentToUser(bool organizationIdNull,
+        ClientType clientType, SutProvider<NotificationHubPushNotificationService> sutProvider,
+        Notification notification)
+    {
+        if (organizationIdNull)
+        {
+            notification.OrganizationId = null;
+        }
+
+        notification.ClientType = clientType;
+        var expectedSyncNotification = ToSyncNotificationPushNotification(notification);
+
+        await sutProvider.Sut.PushSyncNotificationAsync(notification);
+
+        await AssertSendTemplateNotificationAsync(sutProvider, PushType.SyncNotification, expectedSyncNotification,
+            $"(template:payload_userId:{notification.UserId} && clientType:{clientType})");
+        await sutProvider.GetDependency<IInstallationDeviceRepository>()
+            .Received(0)
+            .UpsertAsync(Arg.Any<InstallationDeviceEntity>());
+    }
+
+    [Theory]
+    [BitAutoData]
+    [NotificationCustomize(false)]
+    public async void PushSyncNotificationAsync_UserIdNullOrganizationIdProvidedClientTypeAll_SentToOrganization(
+        SutProvider<NotificationHubPushNotificationService> sutProvider, Notification notification)
+    {
+        notification.UserId = null;
+        notification.ClientType = ClientType.All;
+        var expectedSyncNotification = ToSyncNotificationPushNotification(notification);
+
+        await sutProvider.Sut.PushSyncNotificationAsync(notification);
+
+        await AssertSendTemplateNotificationAsync(sutProvider, PushType.SyncNotification, expectedSyncNotification,
+            $"(template:payload && organizationId:{notification.OrganizationId})");
+        await sutProvider.GetDependency<IInstallationDeviceRepository>()
+            .Received(0)
+            .UpsertAsync(Arg.Any<InstallationDeviceEntity>());
+    }
+
+    [Theory]
+    [BitAutoData(ClientType.Browser)]
+    [BitAutoData(ClientType.Desktop)]
+    [BitAutoData(ClientType.Web)]
+    [BitAutoData(ClientType.Mobile)]
+    [NotificationCustomize(false)]
+    public async void PushSyncNotificationAsync_UserIdNullOrganizationIdProvidedClientTypeNotAll_SentToOrganization(
+        ClientType clientType, SutProvider<NotificationHubPushNotificationService> sutProvider,
+        Notification notification)
+    {
+        notification.UserId = null;
+        notification.ClientType = clientType;
+
+        var expectedSyncNotification = ToSyncNotificationPushNotification(notification);
+
+        await sutProvider.Sut.PushSyncNotificationAsync(notification);
+
+        await AssertSendTemplateNotificationAsync(sutProvider, PushType.SyncNotification, expectedSyncNotification,
+            $"(template:payload && organizationId:{notification.OrganizationId} && clientType:{clientType})");
+        await sutProvider.GetDependency<IInstallationDeviceRepository>()
+            .Received(0)
+            .UpsertAsync(Arg.Any<InstallationDeviceEntity>());
+    }
 
-    private readonly IInstallationDeviceRepository _installationDeviceRepository;
-    private readonly INotificationHubPool _notificationHubPool;
-    private readonly IHttpContextAccessor _httpContextAccessor;
-    private readonly ILogger<NotificationsApiPushNotificationService> _logger;
+    private static SyncNotificationPushNotification ToSyncNotificationPushNotification(Notification notification) =>
+        new()
+        {
+            Id = notification.Id,
+            UserId = notification.UserId,
+            OrganizationId = notification.OrganizationId,
+            ClientType = notification.ClientType,
+            RevisionDate = notification.RevisionDate
+        };
 
-    public NotificationHubPushNotificationServiceTests()
+    private static async Task AssertSendTemplateNotificationAsync(
+        SutProvider<NotificationHubPushNotificationService> sutProvider, PushType type, object payload, string tag)
     {
-        _installationDeviceRepository = Substitute.For<IInstallationDeviceRepository>();
-        _httpContextAccessor = Substitute.For<IHttpContextAccessor>();
-        _notificationHubPool = Substitute.For<INotificationHubPool>();
-        _logger = Substitute.For<ILogger<NotificationsApiPushNotificationService>>();
-
-        _sut = new NotificationHubPushNotificationService(
-            _installationDeviceRepository,
-            _notificationHubPool,
-            _httpContextAccessor,
-            _logger
-        );
+        await sutProvider.GetDependency<INotificationHubPool>()
+            .Received(1)
+            .AllClients
+            .Received(1)
+            .SendTemplateNotificationAsync(
+                Arg.Is<IDictionary<string, string>>(dictionary => MatchingSendPayload(dictionary, type, payload)),
+                tag);
     }
 
-    // Remove this test when we add actual tests. It only proves that
-    // we've properly constructed the system under test.
-    [Fact(Skip = "Needs additional work")]
-    public void ServiceExists()
+    private static bool MatchingSendPayload(IDictionary<string, string> dictionary, PushType type, object payload)
     {
-        Assert.NotNull(_sut);
+        return dictionary.ContainsKey("type") && dictionary["type"].Equals(((byte)type).ToString()) &&
+               dictionary.ContainsKey("payload") && dictionary["payload"].Equals(JsonSerializer.Serialize(payload));
     }
 }