diff --git a/HealthMonitoring.Client/HealthMonitoring.Client.csproj b/HealthMonitoring.Client/HealthMonitoring.Client.csproj
index b8ca7c0..2479244 100644
--- a/HealthMonitoring.Client/HealthMonitoring.Client.csproj
+++ b/HealthMonitoring.Client/HealthMonitoring.Client.csproj
@@ -11,6 +11,7 @@
     <PackageReference Include="Microsoft.Extensions.Http" Version="10.0.12" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="10.0.12" />
     <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="10.0.12" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.12" />
   </ItemGroup>
   <ItemGroup>
     <None Include="README.md" Pack="true" PackagePath="" />
diff --git a/HealthMonitoring.Client/HealthMonitoringRegistrationClient.cs b/HealthMonitoring.Client/HealthMonitoringRegistrationClient.cs
index 94c796f..bcc9bf9 100644
--- a/HealthMonitoring.Client/HealthMonitoringRegistrationClient.cs
+++ b/HealthMonitoring.Client/HealthMonitoringRegistrationClient.cs
@@ -1,6 +1,7 @@
 using System.Net.Http.Json;
 using System.Text.Json;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
 
 namespace HealthMonitoring.Client;
 
@@ -38,7 +39,9 @@ public interface IHealthMonitoringRegistrationClient
     Task<ServiceRegistrationResult> RegisterAndConfigureAsync(ServiceRegistrationOptions options, IEnumerable<DependencyMappingOptions> mappings, CancellationToken cancellationToken = default);
 }
 
-public sealed class HealthMonitoringRegistrationClient(HttpClient httpClient) : IHealthMonitoringRegistrationClient
+public sealed class HealthMonitoringRegistrationClient(
+    HttpClient httpClient,
+    ILogger<HealthMonitoringRegistrationClient>? logger = null) : IHealthMonitoringRegistrationClient
 {
     private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web);
 
@@ -47,7 +50,7 @@ public async Task<ServiceRegistrationResult> RegisterAsync(ServiceRegistrationOp
         ArgumentNullException.ThrowIfNull(options);
         ValidateServiceOptions(options);
 
-        using var response = await httpClient.PostAsJsonAsync("api/services/register", new ServiceRegistrationPayload(
+        var payload = new ServiceRegistrationPayload(
             options.ServiceId,
             options.Name,
             options.HealthUrl.ToString(),
@@ -61,7 +64,19 @@ public async Task<ServiceRegistrationResult> RegisterAsync(ServiceRegistrationOp
             options.Group,
             options.Description,
             options.Version,
-            options.Host), JsonOptions, cancellationToken);
+            options.Host);
+
+        var loggedPayload = payload with
+        {
+            ConnectionString = string.IsNullOrWhiteSpace(payload.ConnectionString)
+                ? payload.ConnectionString
+                : "[REDACTED]"
+        };
+        logger?.LogInformation(
+            "POST /api/services/register body: {RequestBody}",
+            JsonSerializer.Serialize(loggedPayload, JsonOptions));
+
+        using var response = await httpClient.PostAsJsonAsync("api/services/register", payload, JsonOptions, cancellationToken);
 
         await EnsureSuccessAsync(response, "register service", cancellationToken);
         var result = await response.Content.ReadFromJsonAsync<ServiceRegistrationResponsePayload>(JsonOptions, cancellationToken)
diff --git a/HealthMonitoring.Tests/Api/ServiceRegistrationLoggingTests.cs b/HealthMonitoring.Tests/Api/ServiceRegistrationLoggingTests.cs
new file mode 100644
index 0000000..c0d1a77
--- /dev/null
+++ b/HealthMonitoring.Tests/Api/ServiceRegistrationLoggingTests.cs
@@ -0,0 +1,23 @@
+using HealthMonitoring.Api;
+using HealthMonitoring.Domain;
+
+namespace HealthMonitoring.Tests.Api;
+
+public sealed class ServiceRegistrationLoggingTests
+{
+    [Fact]
+    public void Registration_body_for_logging_redacts_connection_strings()
+    {
+        var request = new ServiceRegistrationRequest("orders-db", "Orders DB", "https://orders/health")
+        {
+            MonitorType = MonitorType.SqlServer,
+            ConnectionString = "Server=orders;Database=Orders;Authentication=Integrated Security"
+        };
+
+        var body = ServiceRegistrationLogFormatter.Serialize(request);
+
+        Assert.Contains("orders-db", body);
+        Assert.Contains("[REDACTED]", body);
+        Assert.DoesNotContain("Integrated Security", body);
+    }
+}
diff --git a/HealthMonitoring.Tests/Client/HealthMonitoringRegistrationClientTests.cs b/HealthMonitoring.Tests/Client/HealthMonitoringRegistrationClientTests.cs
index 167cb6f..26feae4 100644
--- a/HealthMonitoring.Tests/Client/HealthMonitoringRegistrationClientTests.cs
+++ b/HealthMonitoring.Tests/Client/HealthMonitoringRegistrationClientTests.cs
@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Http.Json;
 using HealthMonitoring.Client;
+using Microsoft.Extensions.Logging;
 
 namespace HealthMonitoring.Tests.Client;
 
@@ -47,6 +48,37 @@ public async Task RegisterAsync_posts_service_configuration_and_returns_acknowle
         Assert.True(payload.IgnoreCertificateErrors);
     }
 
+    [Fact]
+    public async Task RegisterAsync_logs_the_post_body_without_exposing_connection_strings()
+    {
+        var handler = new RecordingHandler(_ => new HttpResponseMessage(HttpStatusCode.Created)
+        {
+            Content = JsonContent.Create(new
+            {
+                serviceId = PaymentsApiServiceId,
+                action = "created",
+                service = new { id = Guid.Parse("11111111-1111-1111-1111-111111111111") }
+            })
+        });
+        var logger = new RecordingLogger<HealthMonitoringRegistrationClient>();
+        var client = new HealthMonitoringRegistrationClient(
+            new HttpClient(handler) { BaseAddress = new Uri(MonitoringBaseUrl) },
+            logger);
+
+        await client.RegisterAsync(new ServiceRegistrationOptions
+        {
+            ServiceId = PaymentsApiServiceId,
+            Name = "Payments API",
+            HealthUrl = new Uri("https://payments-api/health"),
+            ConnectionString = "Server=secret;Password=super-secret"
+        });
+
+        Assert.Contains("payments-api", logger.Messages.Single());
+        Assert.Contains("/api/services/register", logger.Messages.Single());
+        Assert.Contains("REDACTED", logger.Messages.Single());
+        Assert.DoesNotContain("super-secret", logger.Messages.Single());
+    }
+
     [Fact]
     public async Task SetDependencyMappingsAsync_resolves_target_service_and_upserts_mapping()
     {
@@ -133,6 +165,26 @@ protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage reques
         }
     }
 
+    private sealed class RecordingLogger<T> : ILogger<T>
+    {
+        public List<string> Messages { get; } = [];
+
+        public IDisposable? BeginScope<TState>(TState state) where TState : notnull
+        {
+            _ = state;
+            return null;
+        }
+
+        public bool IsEnabled(LogLevel logLevel) => logLevel != LogLevel.None;
+
+        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+        {
+            _ = logLevel;
+            _ = eventId;
+            Messages.Add(formatter(state, exception));
+        }
+    }
+
     private static HttpResponseMessage JsonResponse(HttpStatusCode statusCode, object value) => new(statusCode)
     {
         Content = JsonContent.Create(value)
diff --git a/HealthMonitoring/Api/ServiceRegistrationEndpoints.cs b/HealthMonitoring/Api/ServiceRegistrationEndpoints.cs
index 6ae9ff5..ad7c532 100644
--- a/HealthMonitoring/Api/ServiceRegistrationEndpoints.cs
+++ b/HealthMonitoring/Api/ServiceRegistrationEndpoints.cs
@@ -1,5 +1,7 @@
 using HealthMonitoring.Domain;
 using HealthMonitoring.Persistence;
+using System.Text.Json;
+using Microsoft.Extensions.Logging;
 
 namespace HealthMonitoring.Api;
 
@@ -17,8 +19,12 @@ public static IEndpointRouteBuilder MapServiceRegistrationEndpoints(this IEndpoi
     }
 
     private static void MapRegistrationEndpoint(IEndpointRouteBuilder endpoints, string dashboardEnvironment) =>
-        endpoints.MapPost("/api/services/register", async (ServiceRegistrationRequest request, IHealthMonitoringRepository repository, CancellationToken cancellationToken) =>
+        endpoints.MapPost("/api/services/register", async (ServiceRegistrationRequest request, IHealthMonitoringRepository repository, ILoggerFactory loggerFactory, CancellationToken cancellationToken) =>
         {
+            loggerFactory.CreateLogger("HealthMonitoring.Api.ServiceRegistrationEndpoints").LogInformation(
+                "POST /api/services/register body: {RequestBody}",
+                ServiceRegistrationLogFormatter.Serialize(request));
+
             var errors = ServiceConfigurationValidator.Validate(request);
             if (errors.Count > 0) return Results.ValidationProblem(errors.ToDictionary(error => error, error => new[] { error }));
 
@@ -72,3 +78,29 @@ private static void MapArchiveEndpoint(IEndpointRouteBuilder endpoints) =>
             return Results.NoContent();
         });
 }
+
+public static class ServiceRegistrationLogFormatter
+{
+    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web);
+
+    public static string Serialize(ServiceRegistrationRequest request) =>
+        JsonSerializer.Serialize(new
+        {
+            request.ServiceId,
+            request.Name,
+            request.HealthUrl,
+            request.MonitorType,
+            ConnectionString = string.IsNullOrWhiteSpace(request.ConnectionString)
+                ? request.ConnectionString
+                : "[REDACTED]",
+            request.IgnoreCertificateErrors,
+            request.PollingIntervalSeconds,
+            request.RequestTimeoutSeconds,
+            request.RetentionDays,
+            request.StatusPolicy,
+            request.Group,
+            request.Description,
+            request.Version,
+            request.Host
+        }, JsonOptions);
+}
diff --git a/HealthMonitoring/appsettings.json b/HealthMonitoring/appsettings.json
index 827c5d3..8a4c2cd 100644
--- a/HealthMonitoring/appsettings.json
+++ b/HealthMonitoring/appsettings.json
@@ -5,7 +5,8 @@
   "Logging": {
     "LogLevel": {
       "Default": "Information",
-      "Microsoft.AspNetCore": "Warning"
+      "Microsoft.AspNetCore": "Warning",
+      "Microsoft.EntityFrameworkCore": "Warning"
     }
   },
   "Initialization": {