diff --git a/src/Spark.Engine/Extensions/NetCore/IServiceCollectionExtensions.cs b/src/Spark.Engine/Extensions/NetCore/IServiceCollectionExtensions.cs
index 36ef7488d..bd97ab853 100644
--- a/src/Spark.Engine/Extensions/NetCore/IServiceCollectionExtensions.cs
+++ b/src/Spark.Engine/Extensions/NetCore/IServiceCollectionExtensions.cs
@@ -99,12 +99,24 @@ public static IMvcCoreBuilder AddFhirFormatters(this IServiceCollection services
 
             return services.AddMvcCore(options =>
             {
-                options.InputFormatters.Add(new ResourceJsonInputFormatter(new FhirJsonParser(settings.ParserSettings), ArrayPool<char>.Shared));
-                options.InputFormatters.Add(new ResourceXmlInputFormatter(new FhirXmlParser(settings.ParserSettings)));
-                options.InputFormatters.Add(new BinaryInputFormatter());
-                options.OutputFormatters.Add(new ResourceJsonOutputFormatter());
-                options.OutputFormatters.Add(new ResourceXmlOutputFormatter());
-                options.OutputFormatters.Add(new BinaryOutputFormatter());
+                if (settings.UseAsynchronousIO)
+                {
+                    options.InputFormatters.Add(new AsyncResourceJsonInputFormatter(new FhirJsonParser(settings.ParserSettings)));
+                    options.InputFormatters.Add(new AsyncResourceXmlInputFormatter(new FhirXmlParser(settings.ParserSettings)));
+                    options.InputFormatters.Add(new BinaryInputFormatter());
+                    options.OutputFormatters.Add(new AsyncResourceJsonOutputFormatter());
+                    options.OutputFormatters.Add(new AsyncResourceXmlOutputFormatter());
+                    options.OutputFormatters.Add(new BinaryOutputFormatter());
+                }
+                else
+                {
+                    options.InputFormatters.Add(new ResourceJsonInputFormatter(new FhirJsonParser(settings.ParserSettings), ArrayPool<char>.Shared));
+                    options.InputFormatters.Add(new ResourceXmlInputFormatter(new FhirXmlParser(settings.ParserSettings)));
+                    options.InputFormatters.Add(new BinaryInputFormatter());
+                    options.OutputFormatters.Add(new ResourceJsonOutputFormatter());
+                    options.OutputFormatters.Add(new ResourceXmlOutputFormatter());
+                    options.OutputFormatters.Add(new BinaryOutputFormatter());
+                }
 
                 options.RespectBrowserAcceptHeader = true;
 
diff --git a/src/Spark.Engine/Formatters/NetCore/AsyncResourceJsonInputFormatter.cs b/src/Spark.Engine/Formatters/NetCore/AsyncResourceJsonInputFormatter.cs
new file mode 100644
index 000000000..72cdd50ff
--- /dev/null
+++ b/src/Spark.Engine/Formatters/NetCore/AsyncResourceJsonInputFormatter.cs
@@ -0,0 +1,64 @@
+#if NETSTANDARD2_0
+using Hl7.Fhir.Model;
+using Hl7.Fhir.Serialization;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Formatters;
+using Microsoft.AspNetCore.WebUtilities;
+using Newtonsoft.Json;
+using Spark.Core;
+using Spark.Engine.Extensions;
+using System;
+using System.Buffers;
+using System.Diagnostics;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Spark.Engine.Formatters
+{
+    public class AsyncResourceJsonInputFormatter : TextInputFormatter
+    {
+        private readonly FhirJsonParser _parser;
+
+        public AsyncResourceJsonInputFormatter(FhirJsonParser parser)
+        {
+            _parser = parser ?? throw new ArgumentNullException(nameof(parser));
+
+            SupportedEncodings.Clear();
+            SupportedEncodings.Add(Encoding.UTF8);
+
+            SupportedMediaTypes.Add("application/json");
+            SupportedMediaTypes.Add("application/fhir+json");
+            SupportedMediaTypes.Add("application/json+fhir");
+            SupportedMediaTypes.Add("text/json");
+        }
+
+        protected override bool CanReadType(Type type)
+        {
+            return typeof(Resource).IsAssignableFrom(type);
+        }
+
+        public override async Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (encoding == null) throw new ArgumentNullException(nameof(encoding));
+            if (encoding != Encoding.UTF8)
+                throw Error.BadRequest("FHIR supports UTF-8 encoding exclusively, not " + encoding.WebName);
+
+            try
+            {
+                using var reader = new StreamReader(context.HttpContext.Request.Body, Encoding.UTF8);
+                var body = await reader.ReadToEndAsync();
+                var resource = _parser.Parse<Resource>(body);
+                context.HttpContext.AddResourceType(resource.GetType());
+
+                return await InputFormatterResult.SuccessAsync(resource);
+            }
+            catch (FormatException exception)
+            {
+                throw Error.BadRequest($"Body parsing failed: {exception.Message}");
+            }
+        }
+    }
+}
+#endif
\ No newline at end of file
diff --git a/src/Spark.Engine/Formatters/NetCore/AsyncResourceJsonOutputFormatter.cs b/src/Spark.Engine/Formatters/NetCore/AsyncResourceJsonOutputFormatter.cs
new file mode 100644
index 000000000..07e992dbc
--- /dev/null
+++ b/src/Spark.Engine/Formatters/NetCore/AsyncResourceJsonOutputFormatter.cs
@@ -0,0 +1,95 @@
+#if NETSTANDARD2_0
+using FhirModel = Hl7.Fhir.Model;
+using Hl7.Fhir.Rest;
+using Hl7.Fhir.Serialization;
+using Microsoft.AspNetCore.Mvc.Formatters;
+using Newtonsoft.Json;
+using Spark.Core;
+using Spark.Engine.Core;
+using Spark.Engine.Extensions;
+using System;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using System.Net;
+
+namespace Spark.Engine.Formatters
+{
+    public class AsyncResourceJsonOutputFormatter : TextOutputFormatter
+    {
+        public static readonly string[] JsonMediaTypes =
+        {
+            "application/json",
+            "application/fhir+json",
+            "application/json+fhir",
+            "text/json"
+        };
+
+        public AsyncResourceJsonOutputFormatter()
+        {
+            SupportedEncodings.Clear();
+            SupportedEncodings.Add(Encoding.UTF8);
+
+            foreach (var mediaType in JsonMediaTypes)
+            {
+                SupportedMediaTypes.Add(mediaType);
+            }
+        }
+
+        protected override bool CanWriteType(Type type)
+        {
+            return typeof(FhirModel.Resource).IsAssignableFrom(type) 
+                || typeof(FhirResponse).IsAssignableFrom(type)
+                || typeof(ValidationProblemDetails).IsAssignableFrom(type);
+        }
+
+        public override async Task WriteResponseBodyAsync(OutputFormatterWriteContext context, Encoding selectedEncoding)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (selectedEncoding == null) throw new ArgumentNullException(nameof(selectedEncoding));
+            if (selectedEncoding != Encoding.UTF8) throw Error.BadRequest($"FHIR supports UTF-8 encoding exclusively, not {selectedEncoding.WebName}");
+
+            if (!(context.HttpContext.RequestServices.GetService(typeof(FhirJsonSerializer)) is FhirJsonSerializer serializer))
+                throw Error.Internal($"Missing required dependency '{nameof(FhirJsonSerializer)}'");
+
+            var responseBody = context.HttpContext.Response.Body;
+            var writeBodyString = string.Empty;
+            var summaryType = context.HttpContext.Request.RequestSummary();
+
+            if (typeof(FhirResponse).IsAssignableFrom(context.ObjectType))
+            {
+                FhirResponse response = context.Object as FhirResponse;
+
+                context.HttpContext.Response.AcquireHeaders(response);
+                context.HttpContext.Response.StatusCode = (int)response.StatusCode;
+
+                if (response.Resource != null)
+                {
+                    writeBodyString = serializer.SerializeToString(response.Resource, summaryType);
+                }
+            }
+            else if (context.ObjectType == typeof(FhirModel.OperationOutcome) || typeof(FhirModel.Resource).IsAssignableFrom(context.ObjectType))
+            {
+                if (context.Object != null)
+                {
+                    writeBodyString = serializer.SerializeToString(context.Object as FhirModel.Resource, summaryType);
+                }
+            }
+            else if (context.Object is ValidationProblemDetails validationProblems)
+            {
+                FhirModel.OperationOutcome outcome = new FhirModel.OperationOutcome();
+                outcome.AddValidationProblems(context.HttpContext.GetResourceType(), (HttpStatusCode)context.HttpContext.Response.StatusCode, validationProblems);
+                writeBodyString = serializer.SerializeToString(outcome, summaryType);
+            }
+
+            if (!string.IsNullOrWhiteSpace(writeBodyString))
+            {
+                var writeBuffer = selectedEncoding.GetBytes(writeBodyString);
+                await responseBody.WriteAsync(writeBuffer, 0, writeBuffer.Length);
+                await responseBody.FlushAsync();
+            }
+        }
+    }
+}
+#endif
\ No newline at end of file
diff --git a/src/Spark.Engine/Formatters/NetCore/AsyncResourceXmlInputFormatter.cs b/src/Spark.Engine/Formatters/NetCore/AsyncResourceXmlInputFormatter.cs
new file mode 100644
index 000000000..1cd691ddb
--- /dev/null
+++ b/src/Spark.Engine/Formatters/NetCore/AsyncResourceXmlInputFormatter.cs
@@ -0,0 +1,65 @@
+#if NETSTANDARD2_0
+using Hl7.Fhir.Model;
+using Hl7.Fhir.Serialization;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Formatters;
+using Microsoft.AspNetCore.WebUtilities;
+using Spark.Core;
+using Spark.Engine.Extensions;
+using Spark.Engine.IO;
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using System.Xml;
+
+namespace Spark.Engine.Formatters
+{
+    public class AsyncResourceXmlInputFormatter : TextInputFormatter
+    {
+        private readonly FhirXmlParser _parser;
+
+        public AsyncResourceXmlInputFormatter(FhirXmlParser parser)
+        {
+            _parser = parser;
+
+            SupportedEncodings.Clear();
+            SupportedEncodings.Add(Encoding.UTF8);
+
+            SupportedMediaTypes.Add("application/xml");
+            SupportedMediaTypes.Add("application/fhir+xml");
+            SupportedMediaTypes.Add("application/xml+fhir");
+            SupportedMediaTypes.Add("text/xml");
+            SupportedMediaTypes.Add("text/xml+fhir");
+        }
+
+        protected override bool CanReadType(Type type)
+        {
+            return typeof(Resource).IsAssignableFrom(type);
+        }
+
+        public override async Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (encoding == null) throw new ArgumentNullException(nameof(encoding));
+            if (encoding != Encoding.UTF8)
+                throw Error.BadRequest("FHIR supports UTF-8 encoding exclusively, not " + encoding.WebName);
+
+            try
+            {
+                using var reader = new StreamReader(context.HttpContext.Request.Body, Encoding.UTF8);
+                var body = await reader.ReadToEndAsync();
+                var resource = _parser.Parse<Resource>(body);
+                context.HttpContext.AddResourceType(resource.GetType());
+
+                return await InputFormatterResult.SuccessAsync(resource);
+            }
+            catch (FormatException exception)
+            {
+                throw Error.BadRequest($"Body parsing failed: {exception.Message}");
+            }
+        }
+    }
+}
+#endif
\ No newline at end of file
diff --git a/src/Spark.Engine/Formatters/NetCore/AsyncResourceXmlOutputFormatter.cs b/src/Spark.Engine/Formatters/NetCore/AsyncResourceXmlOutputFormatter.cs
new file mode 100644
index 000000000..6986b6429
--- /dev/null
+++ b/src/Spark.Engine/Formatters/NetCore/AsyncResourceXmlOutputFormatter.cs
@@ -0,0 +1,97 @@
+#if NETSTANDARD2_0
+using FhirModel = Hl7.Fhir.Model;
+using Hl7.Fhir.Rest;
+using Hl7.Fhir.Serialization;
+using Microsoft.AspNetCore.Mvc.Formatters;
+using Spark.Core;
+using Spark.Engine.Core;
+using Spark.Engine.Extensions;
+using System;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using System.Xml;
+using Microsoft.AspNetCore.Mvc;
+using System.Net;
+
+namespace Spark.Engine.Formatters
+{
+    public class AsyncResourceXmlOutputFormatter : TextOutputFormatter
+    {
+        public static readonly string[] XmlMediaTypes =
+        {
+            "application/xml",
+            "application/fhir+xml",
+            "application/xml+fhir",
+            "text/xml",
+            "text/xml+fhir"
+        };
+
+        public AsyncResourceXmlOutputFormatter()
+        {
+            SupportedEncodings.Clear();
+            SupportedEncodings.Add(Encoding.UTF8);
+
+            foreach (var mediaType in XmlMediaTypes)
+            {
+                SupportedMediaTypes.Add(mediaType);
+            }
+        }
+
+        protected override bool CanWriteType(Type type)
+        {
+            return 
+                typeof(FhirModel.Resource).IsAssignableFrom(type) 
+                || typeof(FhirResponse).IsAssignableFrom(type)
+                || typeof(ValidationProblemDetails).IsAssignableFrom(type);
+        }
+
+        public override async Task WriteResponseBodyAsync(OutputFormatterWriteContext context, Encoding selectedEncoding)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (selectedEncoding == null) throw new ArgumentNullException(nameof(selectedEncoding));
+            if (selectedEncoding != Encoding.UTF8) throw Error.BadRequest($"FHIR supports UTF-8 encoding exclusively, not {selectedEncoding.WebName}");
+
+            if (!(context.HttpContext.RequestServices.GetService(typeof(FhirXmlSerializer)) is FhirXmlSerializer serializer))
+                throw Error.Internal($"Missing required dependency '{nameof(FhirXmlSerializer)}'");
+
+            var responseBody = context.HttpContext.Response.Body;
+            var writeBodyString = string.Empty;
+            var summaryType = context.HttpContext.Request.RequestSummary();
+
+            if (typeof(FhirResponse).IsAssignableFrom(context.ObjectType))
+            {
+                FhirResponse response = context.Object as FhirResponse;
+
+                context.HttpContext.Response.AcquireHeaders(response);
+                context.HttpContext.Response.StatusCode = (int)response.StatusCode;
+
+                if (response.Resource != null)
+                {
+                    writeBodyString = serializer.SerializeToString(response.Resource, summaryType);
+                }
+            }
+            else if (context.ObjectType == typeof(FhirModel.OperationOutcome) || typeof(FhirModel.Resource).IsAssignableFrom(context.ObjectType))
+            {
+                if (context.Object != null)
+                {
+                    writeBodyString = serializer.SerializeToString(context.Object as FhirModel.Resource, summaryType);
+                }
+            }
+            else if (context.Object is ValidationProblemDetails validationProblems)
+            {
+                FhirModel.OperationOutcome outcome = new FhirModel.OperationOutcome();
+                outcome.AddValidationProblems(context.HttpContext.GetResourceType(), (HttpStatusCode)context.HttpContext.Response.StatusCode, validationProblems);
+                writeBodyString = serializer.SerializeToString(outcome, summaryType);
+            }
+
+            if (!string.IsNullOrWhiteSpace(writeBodyString))
+            {
+                var writeBuffer = selectedEncoding.GetBytes(writeBodyString);
+                await responseBody.WriteAsync(writeBuffer, 0, writeBuffer.Length);
+                await responseBody.FlushAsync();
+            }
+        }
+    }
+}
+#endif
diff --git a/src/Spark.Engine/SparkSettings.cs b/src/Spark.Engine/SparkSettings.cs
index 45ac398d3..31f66d318 100644
--- a/src/Spark.Engine/SparkSettings.cs
+++ b/src/Spark.Engine/SparkSettings.cs
@@ -9,6 +9,7 @@ namespace Spark.Engine
     public class SparkSettings
     {
         public Uri Endpoint { get; set; }
+        public bool UseAsynchronousIO { get; set; }
         public ParserSettings ParserSettings { get; set; }
         public SerializerSettings SerializerSettings { get; set; }
         public ExportSettings ExportSettings { get; set; }