2.3.0

.github/copilot-instructions.md

@@ -1,4 +0,0 @@
-# Copilot Instructions
-
-## Project Guidelines
-- All new byte[xx] calls should use using var data = ArrayPool<byte>.Shared.Lease(xx); instead of directly allocating byte arrays

.github/instructions/instructions.md

@@ -0,0 +1,15 @@
+---
+description: 'Guidelines for this solution'
+applyTo: '**/*.csproj, **/*.cs'
+---
+
+# Multi .NET Framework Targeting
+
+## Instructions
+- The main project "WireMock.Net.Minimal" targets `netstandard2.0` and `net8.0`. Ensure that any new code or dependencies are compatible with these frameworks.
+
+
+# C# Guidelines
+
+## Instructions
+- When a new ByteArray is needed, do not use `var data = new byte[bufferSize];`. Always use `var data = ArrayPool<byte>.Shared.Lease(bufferSize);`.

CHANGELOG.md

@@ -1,3 +1,14 @@
+# 2.3.0 (20 April 2026)
+- [#1436](https://github.com/wiremock/WireMock.Net/pull/1436) - Moving Scenario state change before global response delay is set [feature] contributed by [jayaraman-venkatesan](https://github.com/jayaraman-venkatesan)
+- [#1440](https://github.com/wiremock/WireMock.Net/pull/1440) - Bump log4net from 2.0.15 to 3.3.0 [dependencies] contributed by [dependabot[bot]](https://github.com/apps/dependabot)
+- [#1443](https://github.com/wiremock/WireMock.Net/pull/1443) - Fix ExactMatcher and JsonMatcher not working for ISO dates as string [bug] contributed by [StefH](https://github.com/StefH)
+- [#1444](https://github.com/wiremock/WireMock.Net/pull/1444) - Update instructions.md [refactor] contributed by [StefH](https://github.com/StefH)
+- [#1448](https://github.com/wiremock/WireMock.Net/pull/1448) - Use DefaultJsonSerializer for BodyAsJson-Response [bug] contributed by [StefH](https://github.com/StefH)
+- [#1205](https://github.com/wiremock/WireMock.Net/issues/1205) - System.Private.Uri 4.3.0 Blackduck security High vulnerability [bug]
+- [#1260](https://github.com/wiremock/WireMock.Net/issues/1260) - Scenario state change before a response delay timeout ends [bug]
+- [#1441](https://github.com/wiremock/WireMock.Net/issues/1441) - ExactMatcher and JsonMatcher not working for ISO dates in v2.2.0 [bug]
+- [#1446](https://github.com/wiremock/WireMock.Net/issues/1446) - WithBodyAsJson does not return correctly formatted json when using SystemTextJsonConverter [bug]
+
 # 2.2.0 (30 March 2026)
 - [#1433](https://github.com/wiremock/WireMock.Net/pull/1433) - Add comments for ScenarioStateStore related code [refactor] contributed by [StefH](https://github.com/StefH)
 - [#1434](https://github.com/wiremock/WireMock.Net/pull/1434) - Upgrade Scriban.Signed [security] contributed by [StefH](https://github.com/StefH)

Directory.Build.props

@@ -4,7 +4,7 @@
     </PropertyGroup>
 
     <PropertyGroup>
-        <VersionPrefix>2.2.0</VersionPrefix>
+        <VersionPrefix>2.3.0</VersionPrefix>
         <PackageIcon>WireMock.Net-Logo.png</PackageIcon>
         <PackageProjectUrl>https://github.com/wiremock/WireMock.Net</PackageProjectUrl>
         <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>

Generate-ReleaseNotes.cmd

@@ -1,6 +1,6 @@
 rem https://github.com/StefH/GitHubReleaseNotes
 
-SET version=2.2.0
+SET version=2.3.0
 
 GitHubReleaseNotes --output CHANGELOG.md --skip-empty-releases --exclude-labels wontfix test question invalid doc duplicate example environment --version %version% --token %GH_TOKEN%
 

PackageReleaseNotes.txt

@@ -1,5 +1,12 @@
-# 2.2.0 (30 March 2026)
-- #1433 Add comments for ScenarioStateStore related code [refactor]
-- #1434 Upgrade Scriban.Signed [security]
+# 2.3.0 (20 April 2026)
+- #1436 Moving Scenario state change before global response delay is set [feature]
+- #1440 Bump log4net from 2.0.15 to 3.3.0 [dependencies]
+- #1443 Fix ExactMatcher and JsonMatcher not working for ISO dates as string [bug]
+- #1444 Update instructions.md [refactor]
+- #1448 Use DefaultJsonSerializer for BodyAsJson-Response [bug]
+- #1205 System.Private.Uri 4.3.0 Blackduck security High vulnerability [bug]
+- #1260 Scenario state change before a response delay timeout ends [bug]
+- #1441 ExactMatcher and JsonMatcher not working for ISO dates in v2.2.0 [bug]
+- #1446 WithBodyAsJson does not return correctly formatted json when using SystemTextJsonConverter [bug]
 
 The full release notes can be found here: https://github.com/wiremock/WireMock.Net/blob/master/CHANGELOG.md

src/WireMock.Net.Extensions.Routing/WireMock.Net.Extensions.Routing.csproj

@@ -25,7 +25,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="JsonConverter.Abstractions" Version="0.8.0" />
+      <PackageReference Include="JsonConverter.Abstractions" Version="0.9.0" />
     </ItemGroup>
 
     <ItemGroup>

src/WireMock.Net.Minimal/Owin/IWireMockMiddlewareOptions.cs

@@ -2,6 +2,7 @@
 
 using System.Collections.Concurrent;
 using System.Security.Cryptography.X509Certificates;
+using JsonConverter.Abstractions;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.DependencyInjection;
 using WireMock.Handlers;
@@ -99,4 +100,12 @@ internal interface IWireMockMiddlewareOptions
     /// WebSocket settings.
     /// </summary>
     WebSocketSettings? WebSocketSettings { get; set; }
+
+    /// <summary>
+    /// Gets or sets the default JSON converter used for serialization.
+    /// </summary>
+    /// <remarks>
+    /// Set this property to customize how objects are serialized to and deserialized from JSON during mapping.
+    /// </remarks>
+    IJsonConverter DefaultJsonSerializer { get; set; }
 }

src/WireMock.Net.Minimal/Owin/Mappers/OwinResponseMapper.cs

@@ -3,249 +3,242 @@
 using System.Globalization;
 using System.Net;
 using System.Text;
+using JsonConverter.Abstractions;
 using Microsoft.AspNetCore.Http;
-using Newtonsoft.Json;
 using RandomDataGenerator.FieldOptions;
 using RandomDataGenerator.Randomizers;
-using Stef.Validation;
 using WireMock.Http;
 using WireMock.ResponseBuilders;
 using WireMock.ResponseProviders;
 using WireMock.Types;
 using WireMock.Util;
 
-namespace WireMock.Owin.Mappers
+namespace WireMock.Owin.Mappers;
+
+/// <summary>
+/// OwinResponseMapper
+/// </summary>
+internal class OwinResponseMapper(IWireMockMiddlewareOptions options) : IOwinResponseMapper
 {
-    /// <summary>
-    /// OwinResponseMapper
-    /// </summary>
-    internal class OwinResponseMapper : IOwinResponseMapper
+    private readonly IRandomizerNumber<double> _randomizerDouble = RandomizerFactory.GetRandomizer(new FieldOptionsDouble { Min = 0, Max = 1 });
+    private readonly IRandomizerBytes _randomizerBytes = RandomizerFactory.GetRandomizer(new FieldOptionsBytes { Min = 100, Max = 200 });
+    private readonly Encoding _utf8NoBom = new UTF8Encoding(false);
+
+    // https://msdn.microsoft.com/en-us/library/78h415ay(v=vs.110).aspx
+    private static readonly IDictionary<string, Action<HttpResponse, bool, WireMockList<string>>> ResponseHeadersToFix =
+        new Dictionary<string, Action<HttpResponse, bool, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase)
+        {
+            { HttpKnownHeaderNames.ContentType, (r, _, v) => r.ContentType = v.FirstOrDefault() },
+            { HttpKnownHeaderNames.ContentLength, (r, hasBody, v) =>
+                {
+                    // Only set the Content-Length header if the response does not have a body
+                    if (!hasBody && long.TryParse(v.FirstOrDefault(), out var contentLength))
+                    {
+                        r.ContentLength = contentLength;
+                    }
+                }
+            }
+        };
+
+    /// <inheritdoc />
+    public async Task MapAsync(IResponseMessage? responseMessage, HttpResponse response)
     {
-        private readonly IRandomizerNumber<double> _randomizerDouble = RandomizerFactory.GetRandomizer(new FieldOptionsDouble { Min = 0, Max = 1 });
-        private readonly IRandomizerBytes _randomizerBytes = RandomizerFactory.GetRandomizer(new FieldOptionsBytes { Min = 100, Max = 200 });
-        private readonly IWireMockMiddlewareOptions _options;
-        private readonly Encoding _utf8NoBom = new UTF8Encoding(false);
-
-        // https://msdn.microsoft.com/en-us/library/78h415ay(v=vs.110).aspx
-        private static readonly IDictionary<string, Action<HttpResponse, bool, WireMockList<string>>> ResponseHeadersToFix =
-            new Dictionary<string, Action<HttpResponse, bool, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase)
-            {
-                { HttpKnownHeaderNames.ContentType, (r, _, v) => r.ContentType = v.FirstOrDefault() },
-                { HttpKnownHeaderNames.ContentLength, (r, hasBody, v) =>
-                    {
-                        // Only set the Content-Length header if the response does not have a body
-                        if (!hasBody && long.TryParse(v.FirstOrDefault(), out var contentLength))
-                        {
-                            r.ContentLength = contentLength;
-                        }
-                    }
-                }
-            };
-
-        /// <summary>
-        /// Constructor
-        /// </summary>
-        /// <param name="options">The IWireMockMiddlewareOptions.</param>
-        public OwinResponseMapper(IWireMockMiddlewareOptions options)
+        if (responseMessage == null || responseMessage is WebSocketHandledResponse)
         {
-            _options = Guard.NotNull(options);
+            return;
         }
 
-        /// <inheritdoc />
-        public async Task MapAsync(IResponseMessage? responseMessage, HttpResponse response)
+        var bodyData = responseMessage.BodyData;
+        if (bodyData?.GetDetectedBodyType() == BodyType.SseString)
         {
-            if (responseMessage == null || responseMessage is WebSocketHandledResponse)
-            {
-                return;
-            }
+            await HandleSseStringAsync(responseMessage, response, bodyData);
+            return;
+        }
 
-            var bodyData = responseMessage.BodyData;
-            if (bodyData?.GetDetectedBodyType() == BodyType.SseString)
-            {
-                await HandleSseStringAsync(responseMessage, response, bodyData);
-                return;
-            }
+        byte[]? bytes;
+        switch (responseMessage.FaultType)
+        {
+            case FaultType.EMPTY_RESPONSE:
+                bytes = IsFault(responseMessage) ? [] : await GetNormalBodyAsync(responseMessage).ConfigureAwait(false);
+                break;
 
-            byte[]? bytes;
-            switch (responseMessage.FaultType)
-            {
-                case FaultType.EMPTY_RESPONSE:
-                    bytes = IsFault(responseMessage) ? [] : await GetNormalBodyAsync(responseMessage).ConfigureAwait(false);
-                    break;
-
-                case FaultType.MALFORMED_RESPONSE_CHUNK:
-                    bytes = await GetNormalBodyAsync(responseMessage).ConfigureAwait(false) ?? [];
-                    if (IsFault(responseMessage))
-                    {
-                        bytes = bytes.Take(bytes.Length / 2).Union(_randomizerBytes.Generate()).ToArray();
-                    }
-                    break;
-
-                default:
-                    bytes = await GetNormalBodyAsync(responseMessage).ConfigureAwait(false);
-                    break;
-            }
-
-            if (responseMessage.StatusCode is HttpStatusCode or int)
-            {
-                response.StatusCode = MapStatusCode((int) responseMessage.StatusCode);
-            }
-            else if (responseMessage.StatusCode is string statusCodeAsString)
-            {
-                // Note: this case will also match on null
-                _ = int.TryParse(statusCodeAsString, out var statusCodeTypeAsInt);
-                response.StatusCode = MapStatusCode(statusCodeTypeAsInt);
-            }
-
-            SetResponseHeaders(responseMessage, bytes != null, response);
-
-            if (bytes != null)
-            {
-                try
+            case FaultType.MALFORMED_RESPONSE_CHUNK:
+                bytes = await GetNormalBodyAsync(responseMessage).ConfigureAwait(false) ?? [];
+                if (IsFault(responseMessage))
                 {
-                    await response.Body.WriteAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
+                    bytes = bytes.Take(bytes.Length / 2).Union(_randomizerBytes.Generate()).ToArray();
                 }
-                catch (Exception ex)
+                break;
+
+            default:
+                bytes = await GetNormalBodyAsync(responseMessage).ConfigureAwait(false);
+                break;
+        }
+
+        if (responseMessage.StatusCode is HttpStatusCode or int)
+        {
+            response.StatusCode = MapStatusCode((int)responseMessage.StatusCode);
+        }
+        else if (responseMessage.StatusCode is string statusCodeAsString)
+        {
+            // Note: this case will also match on null
+            _ = int.TryParse(statusCodeAsString, out var statusCodeTypeAsInt);
+            response.StatusCode = MapStatusCode(statusCodeTypeAsInt);
+        }
+
+        SetResponseHeaders(responseMessage, bytes != null, response);
+
+        if (bytes != null)
+        {
+            try
+            {
+                await response.Body.WriteAsync(bytes, 0, bytes.Length).ConfigureAwait(false);
+            }
+            catch (Exception ex)
+            {
+                options.Logger.Warn("Error writing response body. Exception : {0}", ex);
+            }
+        }
+
+        SetResponseTrailingHeaders(responseMessage, response);
+    }
+
+    private static async Task HandleSseStringAsync(IResponseMessage responseMessage, HttpResponse response, IBodyData bodyData)
+    {
+        if (bodyData.SseStringQueue == null)
+        {
+            return;
+        }
+
+        SetResponseHeaders(responseMessage, true, response);
+
+        string? text;
+        do
+        {
+            if (bodyData.SseStringQueue.TryRead(out text))
+            {
+                await response.WriteAsync(text);
+                await response.Body.FlushAsync();
+            }
+        } while (text != null);
+    }
+
+    private int MapStatusCode(int code)
+    {
+        if (options.AllowOnlyDefinedHttpStatusCodeInResponse == true && !Enum.IsDefined(typeof(HttpStatusCode), code))
+        {
+            return (int)HttpStatusCode.OK;
+        }
+
+        return code;
+    }
+
+    private bool IsFault(IResponseMessage responseMessage)
+    {
+        return responseMessage.FaultPercentage == null || _randomizerDouble.Generate() <= responseMessage.FaultPercentage;
+    }
+
+    private async Task<byte[]?> GetNormalBodyAsync(IResponseMessage responseMessage)
+    {
+        var bodyData = responseMessage.BodyData;
+        switch (bodyData?.GetDetectedBodyType())
+        {
+            case BodyType.String:
+            case BodyType.FormUrlEncoded:
+                return (bodyData.Encoding ?? _utf8NoBom).GetBytes(bodyData.BodyAsString!);
+
+            case BodyType.Json:
+                var jsonConverterOptions = new JsonConverterOptions
                 {
-                    _options.Logger.Warn("Error writing response body. Exception : {0}", ex);
-                }
-            }
+                    WriteIndented = bodyData.BodyAsJsonIndented == true,
+                    IgnoreNullValues = true
+                };
 
-            SetResponseTrailingHeaders(responseMessage, response);
-        }
+                var jsonBody = options.DefaultJsonSerializer.Serialize(bodyData.BodyAsJson!, jsonConverterOptions);
+                return (bodyData.Encoding ?? _utf8NoBom).GetBytes(jsonBody);
 
-        private static async Task HandleSseStringAsync(IResponseMessage responseMessage, HttpResponse response, IBodyData bodyData)
-        {
-            if (bodyData.SseStringQueue == null)
-            {
-                return;
-            }
-
-            SetResponseHeaders(responseMessage, true, response);
-
-            string? text;
-            do
-            {
-                if (bodyData.SseStringQueue.TryRead(out text))
+            case BodyType.ProtoBuf:
+                if (TypeLoader.TryLoadStaticInstance<IProtoBufUtils>(out var protoBufUtils))
                 {
-                    await response.WriteAsync(text);
-                    await response.Body.FlushAsync();
+                    var protoDefinitions = bodyData.ProtoDefinition?.Invoke().Texts;
+                    return await protoBufUtils.GetProtoBufMessageWithHeaderAsync(protoDefinitions, bodyData.ProtoBufMessageType, bodyData.BodyAsJson).ConfigureAwait(false);
                 }
-            } while (text != null);
+                break;
+
+            case BodyType.Bytes:
+                return bodyData.BodyAsBytes;
+
+            case BodyType.File:
+                return options.FileSystemHandler?.ReadResponseBodyAsFile(bodyData.BodyAsFile!);
+
+            case BodyType.MultiPart:
+                options.Logger.Warn("MultiPart body type is not handled!");
+                break;
+
+            case BodyType.None:
+                break;
         }
 
-        private int MapStatusCode(int code)
+        return null;
+    }
+
+    private static void SetResponseHeaders(IResponseMessage responseMessage, bool hasBody, HttpResponse response)
+    {
+        // Force setting the Date header (#577)
+        AppendResponseHeader(
+            response,
+            HttpKnownHeaderNames.Date,
+            [DateTime.UtcNow.ToString(CultureInfo.InvariantCulture.DateTimeFormat.RFC1123Pattern, CultureInfo.InvariantCulture)]
+        );
+
+        // Set other headers
+        foreach (var item in responseMessage.Headers!)
         {
-            if (_options.AllowOnlyDefinedHttpStatusCodeInResponse == true && !Enum.IsDefined(typeof(HttpStatusCode), code))
+            var headerName = item.Key;
+            var value = item.Value;
+            if (ResponseHeadersToFix.TryGetValue(headerName, out var action))
             {
-                return (int)HttpStatusCode.OK;
+                action.Invoke(response, hasBody, value);
             }
-
-            return code;
-        }
-
-        private bool IsFault(IResponseMessage responseMessage)
-        {
-            return responseMessage.FaultPercentage == null || _randomizerDouble.Generate() <= responseMessage.FaultPercentage;
-        }
-
-        private async Task<byte[]?> GetNormalBodyAsync(IResponseMessage responseMessage)
-        {
-            var bodyData = responseMessage.BodyData;
-            switch (bodyData?.GetDetectedBodyType())
+            else
             {
-                case BodyType.String:
-                case BodyType.FormUrlEncoded:
-                    return (bodyData.Encoding ?? _utf8NoBom).GetBytes(bodyData.BodyAsString!);
-
-                case BodyType.Json:
-                    var formatting = bodyData.BodyAsJsonIndented == true ? Formatting.Indented : Formatting.None;
-                    var jsonBody = JsonConvert.SerializeObject(bodyData.BodyAsJson, new JsonSerializerSettings { Formatting = formatting, NullValueHandling = NullValueHandling.Ignore });
-                    return (bodyData.Encoding ?? _utf8NoBom).GetBytes(jsonBody);
-
-                case BodyType.ProtoBuf:
-                    if (TypeLoader.TryLoadStaticInstance<IProtoBufUtils>(out var protoBufUtils))
-                    {
-                        var protoDefinitions = bodyData.ProtoDefinition?.Invoke().Texts;
-                        return await protoBufUtils.GetProtoBufMessageWithHeaderAsync(protoDefinitions, bodyData.ProtoBufMessageType, bodyData.BodyAsJson).ConfigureAwait(false);
-                    }
-                    break;
-
-                case BodyType.Bytes:
-                    return bodyData.BodyAsBytes;
-
-                case BodyType.File:
-                    return _options.FileSystemHandler?.ReadResponseBodyAsFile(bodyData.BodyAsFile!);
-
-                case BodyType.MultiPart:
-                    _options.Logger.Warn("MultiPart body type is not handled!");
-                    break;
-
-                case BodyType.None:
-                    break;
-            }
-
-            return null;
-        }
-
-        private static void SetResponseHeaders(IResponseMessage responseMessage, bool hasBody, HttpResponse response)
-        {
-            // Force setting the Date header (#577)
-            AppendResponseHeader(
-                response,
-                HttpKnownHeaderNames.Date,
-                [DateTime.UtcNow.ToString(CultureInfo.InvariantCulture.DateTimeFormat.RFC1123Pattern, CultureInfo.InvariantCulture)]
-            );
-
-            // Set other headers
-            foreach (var item in responseMessage.Headers!)
-            {
-                var headerName = item.Key;
-                var value = item.Value;
-                if (ResponseHeadersToFix.TryGetValue(headerName, out var action))
+                // Check if this response header can be added (#148, #227 and #720)
+                if (!HttpKnownHeaderNames.IsRestrictedResponseHeader(headerName))
                 {
-                    action.Invoke(response, hasBody, value);
-                }
-                else
-                {
-                    // Check if this response header can be added (#148, #227 and #720)
-                    if (!HttpKnownHeaderNames.IsRestrictedResponseHeader(headerName))
-                    {
-                        AppendResponseHeader(response, headerName, value.ToArray());
-                    }
+                    AppendResponseHeader(response, headerName, value.ToArray());
                 }
             }
         }
-
-        private static void SetResponseTrailingHeaders(IResponseMessage responseMessage, HttpResponse response)
-        {
-            if (responseMessage.TrailingHeaders == null)
-            {
-                return;
-            }
-
-#if TRAILINGHEADERS
-            foreach (var (headerName, value) in responseMessage.TrailingHeaders)
-            {
-                if (ResponseHeadersToFix.TryGetValue(headerName, out var action))
-                {
-                    action.Invoke(response, false, value);
-                }
-                else
-                {
-                    // Check if this trailing header can be added to the response
-                    if (response.SupportsTrailers() && !HttpKnownHeaderNames.IsRestrictedResponseHeader(headerName))
-                    {
-                        response.AppendTrailer(headerName, new Microsoft.Extensions.Primitives.StringValues(value.ToArray()));
-                    }
-                }
-            }
-#endif
-        }
-
-        private static void AppendResponseHeader(HttpResponse response, string headerName, string[] values)
-        {
-            response.Headers.Append(headerName, values);
-        }
+    }
+
+    private static void SetResponseTrailingHeaders(IResponseMessage responseMessage, HttpResponse response)
+    {
+        if (responseMessage.TrailingHeaders == null)
+        {
+            return;
+        }
+
+#if TRAILINGHEADERS
+        foreach (var (headerName, value) in responseMessage.TrailingHeaders)
+        {
+            if (ResponseHeadersToFix.TryGetValue(headerName, out var action))
+            {
+                action.Invoke(response, false, value);
+            }
+            else
+            {
+                // Check if this trailing header can be added to the response
+                if (response.SupportsTrailers() && !HttpKnownHeaderNames.IsRestrictedResponseHeader(headerName))
+                {
+                    response.AppendTrailer(headerName, new Microsoft.Extensions.Primitives.StringValues(value.ToArray()));
+                }
+            }
+        }
+#endif
+    }
+
+    private static void AppendResponseHeader(HttpResponse response, string headerName, string[] values)
+    {
+        response.Headers.Append(headerName, values);
     }
 }

src/WireMock.Net.Minimal/Owin/WireMockMiddlewareOptions.cs

@@ -2,6 +2,8 @@
 
 using System.Collections.Concurrent;
 using System.Security.Cryptography.X509Certificates;
+using JsonConverter.Abstractions;
+using JsonConverter.Newtonsoft.Json;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.DependencyInjection;
 using WireMock.Handlers;
@@ -108,5 +110,9 @@ internal class WireMockMiddlewareOptions : IWireMockMiddlewareOptions
     /// <inheritdoc />
     public ConcurrentDictionary<Guid, WebSocketConnectionRegistry> WebSocketRegistries { get; } = new();
 
+    /// <inheritdoc />
     public WebSocketSettings? WebSocketSettings { get; set; }
+
+    /// <inheritdoc />
+    public IJsonConverter DefaultJsonSerializer { get; set; } = new NewtonsoftJsonConverter();
 }

src/WireMock.Net.Minimal/Serialization/MappingSerializer.cs

@@ -1,6 +1,7 @@
 // Copyright © WireMock.Net
 
 using JsonConverter.Abstractions;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 #if NETSTANDARD2_0_OR_GREATER || NETCOREAPP3_1_OR_GREATER || NET6_0_OR_GREATER || NET461
 using System.Text.Json;
@@ -10,9 +11,15 @@ namespace WireMock.Serialization;
 
 internal class MappingSerializer(IJsonConverter jsonConverter)
 {
+    private static readonly JsonConverterOptions JsonConverterOptions = new JsonConverterOptions
+    {
+        DateParseHandling = (int) DateParseHandling.None
+    };
+
     internal T[] DeserializeJsonToArray<T>(string value)
     {
-        return DeserializeObjectToArray<T>(jsonConverter.Deserialize<object>(value)!);
+        // DeserializeObject
+        return DeserializeObjectToArray<T>(jsonConverter.Deserialize<object>(value, JsonConverterOptions)!);
     }
 
     internal static T[] DeserializeObjectToArray<T>(object value)

src/WireMock.Net.Minimal/Server/WireMockServer.Admin.cs

@@ -1,6 +1,5 @@
 // Copyright © WireMock.Net
 
-using System.Linq;
 using System.Net;
 using System.Text;
 using JetBrains.Annotations;
@@ -26,9 +25,6 @@ using WireMock.Util;
 
 namespace WireMock.Server;
 
-/// <summary>
-/// The fluent mock server.
-/// </summary>
 public partial class WireMockServer
 {
     private const int EnhancedFileSystemWatcherTimeoutMs = 1000;

src/WireMock.Net.Minimal/Server/WireMockServer.cs

@@ -414,6 +414,7 @@ public partial class WireMockServer : IWireMockServer
         _options.CorsPolicyOptions = _settings.CorsPolicyOptions;
         _options.ClientCertificateMode = (Microsoft.AspNetCore.Server.Kestrel.Https.ClientCertificateMode)_settings.ClientCertificateMode;
         _options.AcceptAnyClientCertificate = _settings.AcceptAnyClientCertificate;
+        _options.DefaultJsonSerializer = _settings.DefaultJsonSerializer;
 
         _httpServer = new AspNetCoreSelfHost(_options, urlOptions);
         var startTask = _httpServer.StartAsync();

src/WireMock.Net.NUnit/WireMock.Net.NUnit.csproj

@@ -25,7 +25,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="JsonConverter.Newtonsoft.Json" Version="0.8.0" />
+        <PackageReference Include="JsonConverter.Newtonsoft.Json" Version="0.9.0" />
         <PackageReference Include="NUnit" Version="4.4.0" />
         <PackageReference Include="Stef.Validation" Version="0.2.0" />
     </ItemGroup>

src/WireMock.Net.RestClient/WireMock.Net.RestClient.csproj

@@ -33,7 +33,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="JsonConverter.Newtonsoft.Json" Version="0.8.0" />
+        <PackageReference Include="JsonConverter.Newtonsoft.Json" Version="0.9.0" />
         <PackageReference Include="RestEase" Version="1.6.4" />
         <PackageReference Include="Stef.Validation" Version="0.2.0" />
     </ItemGroup>

src/WireMock.Net.Shared/WireMock.Net.Shared.csproj

@@ -30,7 +30,7 @@
         <PackageReference Include="Stef.Validation" Version="0.2.0" />
         <PackageReference Include="AnyOf" Version="0.5.0.1" />
         <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="8.0.2" />
-        <PackageReference Include="JsonConverter.Newtonsoft.Json" Version="0.8.0" />
+        <PackageReference Include="JsonConverter.Newtonsoft.Json" Version="0.9.0" />
     </ItemGroup>
 
     <ItemGroup>

test/WireMock.Net.Tests/Owin/Mappers/OwinResponseMapperTests.cs

@@ -9,6 +9,8 @@ using WireMock.Util;
 using WireMock.Owin;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Primitives;
+using JsonConverter.Newtonsoft.Json;
+using JsonConverter.System.Text.Json;
 
 namespace WireMock.Net.Tests.Owin.Mappers;
 
@@ -34,6 +36,7 @@ public class OwinResponseMapperTests
         _optionsMock = new Mock<IWireMockMiddlewareOptions>();
         _optionsMock.SetupAllProperties();
         _optionsMock.SetupGet(o => o.FileSystemHandler).Returns(_fileSystemHandlerMock.Object);
+        _optionsMock.SetupGet(o => o.DefaultJsonSerializer).Returns(new NewtonsoftJsonConverter());
 
         _headers = new Mock<IHeaderDictionary>();
         _headers.SetupAllProperties();
@@ -186,7 +189,7 @@ public class OwinResponseMapperTests
     }
 
     [Fact]
-    public async Task OwinResponseMapper_MapAsync_BodyAsJson()
+    public async Task OwinResponseMapper_MapAsync_BodyAsJson_UsingNewtonsoftJson()
     {
         // Arrange
         var json = new { t = "x", i = (string?)null };
@@ -203,6 +206,25 @@ public class OwinResponseMapperTests
         _stream.Verify(s => s.WriteAsync(new byte[] { 123, 34, 116, 34, 58, 34, 120, 34, 125 }, 0, 9, It.IsAny<CancellationToken>()), Times.Once);
     }
 
+    [Fact]
+    public async Task OwinResponseMapper_MapAsync_BodyAsJson_UsingSystemTextJson()
+    {
+        // Arrange
+        var json = new { t = "x", i = (string?)null };
+        var responseMessage = new ResponseMessage
+        {
+            Headers = new Dictionary<string, WireMockList<string>>(),
+            BodyData = new BodyData { DetectedBodyType = BodyType.Json, BodyAsJson = json, BodyAsJsonIndented = false }
+        };
+        _optionsMock.SetupGet(o => o.DefaultJsonSerializer).Returns(new SystemTextJsonConverter());
+
+        // Act
+        await _sut.MapAsync(responseMessage, _responseMock.Object);
+
+        // Assert
+        _stream.Verify(s => s.WriteAsync(new byte[] { 123, 34, 116, 34, 58, 34, 120, 34, 125 }, 0, 9, It.IsAny<CancellationToken>()), Times.Once);
+    }
+
     [Fact]
     public async Task OwinResponseMapper_MapAsync_SetResponseHeaders()
     {

test/WireMock.Net.Tests/Serialization/MappingSerializerTests.cs

@@ -3,6 +3,8 @@
 using JsonConverter.Newtonsoft.Json;
 using WireMock.Admin.Mappings;
 using WireMock.Serialization;
+using Newtonsoft.Json.Linq;
+
 #if NET8_0_OR_GREATER
 using JsonConverter.System.Text.Json;
 #endif
@@ -319,5 +321,92 @@ public class MappingSerializerTests
         act.Should().Throw<InvalidOperationException>()
             .WithMessage("Cannot deserialize the provided value to an array or object.");
     }
+
+    [Fact]
+    public void MappingSerializer_DeserializeJsonToArray_WithNewtonsoftJson_DateTimeStringInQueryParamExactMatcherPattern_ShouldPreservePatternAsString()
+    {
+        // Arrange
+        var jsonConverter = new NewtonsoftJsonConverter();
+        var serializer = new MappingSerializer(jsonConverter);
+        var mappingJson =
+            """
+            {
+                "Guid": "12345678-1234-1234-1234-aaaaaaaaaaaa",
+                "Request": {
+                    "Path": "/api/report",
+                    "Methods": ["GET"],
+                    "Params": [
+                        {
+                            "Name": "asOfDate",
+                            "Matchers": [
+                                {
+                                    "Name": "ExactMatcher",
+                                    "Pattern": "2021-11-10T13:39:13.705"
+                                }
+                            ]
+                        }
+                    ]
+                },
+                "Response": {
+                    "StatusCode": 200
+                }
+            }
+            """;
+
+        // Act
+        var result = serializer.DeserializeJsonToArray<MappingModel>(mappingJson);
+
+        // Assert
+        result.Should().HaveCount(1);
+        var matcher = result[0].Request!.Params![0].Matchers![0];
+        matcher.Name.Should().Be("ExactMatcher");
+        matcher.Pattern.Should().BeOfType<string>()
+            .Which.Should().Be("2021-11-10T13:39:13.705",
+                "datetime-format strings in ExactMatcher Pattern fields must survive deserialization as strings, " +
+                "not be auto-converted to DateTime by Newtonsoft.Json's DateParseHandling.DateTime");
+    }
+
+    [Fact]
+    public void MappingSerializer_DeserializeJsonToArray_WithNewtonsoftJson_DateTimeStringInJsonMatcherBodyPattern_ShouldPreservePatternAsString()
+    {
+        // Arrange
+        var jsonConverter = new NewtonsoftJsonConverter();
+        var serializer = new MappingSerializer(jsonConverter);
+        // Pattern is an INLINE JSON object (not a string) - this is how WireMock mapping files store
+        // JsonMatcher patterns when recorded. Newtonsoft with DateParseHandling.DateTime will convert
+        // the datetime value inside the JObject to JTokenType.Date during deserialization.
+        var mappingJson =
+            """
+            {
+                "Guid": "12345678-1234-1234-1234-bbbbbbbbbbbb",
+                "Request": {
+                    "Path": "/api/report",
+                    "Methods": ["POST"],
+                    "Body": {
+                        "Matcher": {
+                            "Name": "JsonMatcher",
+                            "Pattern": {"Date": "2021-09-30T00:00:00Z", "Names": ["Cash"]}
+                        }
+                    }
+                },
+                "Response": {
+                    "StatusCode": 200
+                }
+            }
+            """;
+
+        // Act
+        var result = serializer.DeserializeJsonToArray<MappingModel>(mappingJson);
+
+        // Assert - datetime values inside the JObject pattern must remain JTokenType.String.
+        result.Should().HaveCount(1);
+        var matcher = result[0].Request!.Body!.Matcher!;
+        matcher.Name.Should().Be("JsonMatcher");
+        var patternJObject = matcher.Pattern.Should().BeOfType<JObject>().Subject;
+        patternJObject["Date"]!.Type.Should().Be(JTokenType.String,
+            "datetime-format strings inside an inline JsonMatcher body pattern must retain JTokenType.String " +
+            "after deserialization; if DateParseHandling.DateTime auto-converts them to JTokenType.Date, " +
+            "JToken.DeepEquals will fail against incoming request bodies parsed with DateParseHandling.None");
+    }
 #endif
 }

test/WireMock.Net.Tests/WireMockServerTests.WithBody.cs

@@ -4,10 +4,13 @@ using System.Net;
 using System.Net.Http;
 using System.Net.Http.Json;
 using System.Text;
+using System.Text.Json.Serialization;
+using JsonConverter.System.Text.Json;
 using WireMock.Matchers;
 using WireMock.RequestBuilders;
 using WireMock.ResponseBuilders;
 using WireMock.Server;
+using WireMock.Settings;
 
 namespace WireMock.Net.Tests;
 
@@ -18,11 +21,41 @@ public partial class WireMockServerTests
         public string? Hi { get; set; }
     }
 
+    public class Person
+    {
+        [JsonPropertyName("first_name")]
+        public string FirstName { get; set; } = string.Empty;
+
+        [JsonPropertyName("last_name")]
+        public string LastName { get; set; } = string.Empty;
+    }
+
+    [Fact]
+    public async Task WireMockServer_WithBodyAsJson_UsingWireMockServerSettings_SystemTextJsonConverter_ShouldReturnCorrectResponse()
+    {
+        // Arange
+        var person = new Person { FirstName = "John", LastName = "Smith" };
+
+        using var server = WireMockServer.Start(new WireMockServerSettings
+        {
+            DefaultJsonSerializer = new SystemTextJsonConverter()
+        });
+
+        // Act
+        server
+            .Given(Request.Create().UsingAnyMethod())
+            .RespondWith(Response.Create().WithBodyAsJson(person));
+
+        var response = await server.CreateClient().GetStringAsync("/", _ct);
+
+        // Assert
+        response.Should().BeEquivalentTo("{\"first_name\":\"John\",\"last_name\":\"Smith\"}");
+    }
+
     [Fact]
     public async Task WireMockServer_WithBodyAsJson_Using_PostAsJsonAsync_And_MultipleJmesPathMatchers_ShouldMatch()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server.Given(
             Request.Create()
@@ -56,7 +89,7 @@ public partial class WireMockServerTests
         var requestUri = new Uri($"http://localhost:{server.Port}/a");
 
         var json = new { requestId = "1", value = "A" };
-        var response = await server.CreateClient().PostAsJsonAsync(requestUri, json, cancellationToken);
+        var response = await server.CreateClient().PostAsJsonAsync(requestUri, json, _ct);
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
@@ -68,7 +101,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsJson_Using_PostAsJsonAsync_And_MultipleJmesPathMatchers_ShouldMatch_BestMatching()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server.Given(
                 Request.Create()
@@ -105,7 +137,7 @@ public partial class WireMockServerTests
         var requestUri = new Uri($"http://localhost:{server.Port}/a");
 
         var json = new { extra = "X", requestId = "1", value = "A" };
-        var response = await server.CreateClient().PostAsJsonAsync(requestUri, json, cancellationToken);
+        var response = await server.CreateClient().PostAsJsonAsync(requestUri, json, _ct);
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
@@ -117,7 +149,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsJson_Using_PostAsJsonAsync_And_WildcardMatcher_ShouldMatch()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server.Given(
                 Request.Create().UsingPost().WithPath("/foo").WithBody(new WildcardMatcher("*Hello*"))
@@ -132,7 +163,7 @@ public partial class WireMockServerTests
         };
 
         // Act
-        var response = await new HttpClient().PostAsJsonAsync("http://localhost:" + server.Ports[0] + "/foo", jsonObject, cancellationToken);
+        var response = await new HttpClient().PostAsJsonAsync("http://localhost:" + server.Ports[0] + "/foo", jsonObject, _ct);
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
@@ -144,7 +175,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsJson_Using_PostAsync_And_WildcardMatcher_ShouldMatch()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server.Given(
                 Request.Create().UsingPost().WithPath("/foo").WithBody(new WildcardMatcher("*Hello*"))
@@ -154,7 +184,7 @@ public partial class WireMockServerTests
             );
 
         // Act
-        var response = await new HttpClient().PostAsync("http://localhost:" + server.Ports[0] + "/foo", new StringContent("{ Hi = \"Hello World\" }"), cancellationToken);
+        var response = await new HttpClient().PostAsync("http://localhost:" + server.Ports[0] + "/foo", new StringContent("{ Hi = \"Hello World\" }"), _ct);
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
@@ -166,7 +196,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsJson_Using_PostAsync_And_JsonPartialWildcardMatcher_ShouldMatch()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
 
         var matcher = new JsonPartialWildcardMatcher(new { method = "initialize", id = "^[a-f0-9]{32}-[0-9]$" }, ignoreCase: true, regex: true);
@@ -188,13 +217,13 @@ public partial class WireMockServerTests
         // Act
         var content = "{\"jsonrpc\":\"2.0\",\"id\":\"ec475f56d4694b48bc737500ba575b35-1\",\"method\":\"initialize\",\"params\":{\"protocolVersion\":\"2024-11-05\",\"capabilities\":{},\"clientInfo\":{\"name\":\"GitHub Test\",\"version\":\"1.0.0\"}}}";
         var response = await new HttpClient()
-            .PostAsync($"{server.Url}/foo", new StringContent(content, Encoding.UTF8, "application/json"), cancellationToken)
+            .PostAsync($"{server.Url}/foo", new StringContent(content, Encoding.UTF8, "application/json"), _ct)
 ;
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
 
-        var responseText = await response.Content.ReadAsStringAsync(cancellationToken);
+        var responseText = await response.Content.ReadAsStringAsync(_ct);
         responseText.Should().Contain("ec475f56d4694b48bc737500ba575b35-1");
     }
 
@@ -203,8 +232,7 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsJson_Using_PostAsync_And_JsonPartialWildcardMatcher_And_SystemTextJson_ShouldMatch()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
-        using var server = WireMockServer.Start(x => x.DefaultJsonSerializer = new JsonConverter.System.Text.Json.SystemTextJsonConverter() );
+        using var server = WireMockServer.Start(x => x.DefaultJsonSerializer = new SystemTextJsonConverter());
 
         var matcher = new JsonPartialWildcardMatcher(new { id = "^[a-f0-9]{32}-[0-9]$" }, ignoreCase: true, regex: true);
         server.Given(Request.Create()
@@ -220,12 +248,12 @@ public partial class WireMockServerTests
         // Act
         var content = """{"id":"ec475f56d4694b48bc737500ba575b35-1"}""";
         using var httpClient = new HttpClient();
-        var response = await httpClient.PostAsync($"{server.Url}/system-text-json", new StringContent(content, Encoding.UTF8, "application/json"), cancellationToken);
+        var response = await httpClient.PostAsync($"{server.Url}/system-text-json", new StringContent(content, Encoding.UTF8, "application/json"), _ct);
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
 
-        var responseText = await response.Content.ReadAsStringAsync(cancellationToken);
+        var responseText = await response.Content.ReadAsStringAsync(_ct);
         responseText.Should().Contain("OK");
     }
 #endif
@@ -234,7 +262,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsFormUrlEncoded_Using_PostAsync_And_WithFunc()
     {
         // Arrange
-        var cancelationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server.Given(
             Request.Create()
@@ -249,7 +276,7 @@ public partial class WireMockServerTests
         // Act
         var content = new FormUrlEncodedContent([new KeyValuePair<string, string>("key1", "value1")]);
         var response = await new HttpClient()
-            .PostAsync($"{server.Url}/foo", content, cancelationToken);
+            .PostAsync($"{server.Url}/foo", content, _ct);
 
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
@@ -261,7 +288,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsFormUrlEncoded_Using_PostAsync_And_WithExactMatcher()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server.Given(
                 Request.Create()
@@ -282,7 +308,7 @@ public partial class WireMockServerTests
             new KeyValuePair<string, string>("email", "johndoe@example.com")
         ]);
         using var httpClient = new HttpClient();
-        var response = await httpClient.PostAsync($"{server.Url}/foo", content, cancellationToken)
+        var response = await httpClient.PostAsync($"{server.Url}/foo", content, _ct)
 ;
         // Assert
         response.StatusCode.Should().Be(HttpStatusCode.OK);
@@ -294,7 +320,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithBodyAsFormUrlEncoded_Using_PostAsync_And_WithFormUrlEncodedMatcher()
     {
         // Arrange
-        var cancelationToken = TestContext.Current.CancellationToken;
         var matcher = new FormUrlEncodedMatcher(["email=johndoe@example.com", "name=John Doe"]);
         using var server = WireMockServer.Start();
         server.Given(
@@ -326,7 +351,7 @@ public partial class WireMockServerTests
             new KeyValuePair<string, string>("email", "johndoe@example.com")
         ]);
         var responseOrdered = await new HttpClient()
-            .PostAsync($"{server.Url}/foo", contentOrdered, cancelationToken)
+            .PostAsync($"{server.Url}/foo", contentOrdered, _ct)
 ;
 
         // Assert 1
@@ -340,7 +365,7 @@ public partial class WireMockServerTests
             new KeyValuePair<string, string>("name", "John Doe"),
         ]);
         var responseUnordered = await new HttpClient()
-            .PostAsync($"{server.Url}/bar", contentUnordered, cancelationToken)
+            .PostAsync($"{server.Url}/bar", contentUnordered, _ct)
 ;
 
         // Assert 2
@@ -353,7 +378,6 @@ public partial class WireMockServerTests
     public async Task WireMockServer_WithSseBody()
     {
         // Arrange
-        var cancellationToken = TestContext.Current.CancellationToken;
         using var server = WireMockServer.Start();
         server
             .WhenRequest(r => r
@@ -387,9 +411,8 @@ public partial class WireMockServerTests
         using var client = new HttpClient();
 
         // Act 1
-        var normal = await client.GetAsync(server.Url, cancellationToken)
-;
-        (await normal.Content.ReadAsStringAsync(cancellationToken)).Should().Be("normal");
+        var normal = await client.GetAsync(server.Url, _ct);
+        (await normal.Content.ReadAsStringAsync(_ct)).Should().Be("normal");
 
         // Act 2
         using var response = await client.GetStreamAsync($"{server.Url}/sse", _ct);