diff --git a/src/Components/Web.JS/src/Boot.Server.ts b/src/Components/Web.JS/src/Boot.Server.ts
index 824c12546963..307e8e9eed4c 100644
--- a/src/Components/Web.JS/src/Boot.Server.ts
+++ b/src/Components/Web.JS/src/Boot.Server.ts
@@ -10,15 +10,19 @@ import { DotNet } from '@microsoft/dotnet-js-interop';
 import { InitialRootComponentsList } from './Services/InitialRootComponentsList';
 import { JSEventRegistry } from './Services/JSEventRegistry';
 
+type BlazorServerStartOptions = Partial<CircuitStartOptions> & { circuit?: Partial<CircuitStartOptions> };
+
 let started = false;
 
-function boot(userOptions?: Partial<CircuitStartOptions>): Promise<void> {
+function boot(userOptions?: BlazorServerStartOptions): Promise<void> {
   if (started) {
     throw new Error('Blazor has already started.');
   }
   started = true;
 
-  const configuredOptions = resolveOptions(userOptions);
+  // Accept the `circuit` property from the blazor.web.js options format
+  const normalizedOptions = userOptions?.circuit ?? userOptions;
+  const configuredOptions = resolveOptions(normalizedOptions);
   setCircuitOptions(Promise.resolve(configuredOptions || {}));
 
   JSEventRegistry.create(Blazor);
diff --git a/src/Components/Web.JS/src/Boot.WebAssembly.ts b/src/Components/Web.JS/src/Boot.WebAssembly.ts
index a1b106b924c2..df014548cf08 100644
--- a/src/Components/Web.JS/src/Boot.WebAssembly.ts
+++ b/src/Components/Web.JS/src/Boot.WebAssembly.ts
@@ -12,15 +12,19 @@ import { InitialRootComponentsList } from './Services/InitialRootComponentsList'
 import { JSEventRegistry } from './Services/JSEventRegistry';
 import { printErr } from './Platform/Mono/MonoPlatform';
 
+type BlazorWebAssemblyStartOptions = Partial<WebAssemblyStartOptions> & { webAssembly?: Partial<WebAssemblyStartOptions> };
+
 let started = false;
 
-async function boot(options?: Partial<WebAssemblyStartOptions>): Promise<void> {
+async function boot(options?: BlazorWebAssemblyStartOptions): Promise<void> {
   if (started) {
     throw new Error('Blazor has already started.');
   }
   started = true;
 
-  setWebAssemblyOptions(Promise.resolve(options || {}));
+  // Accept the `webAssembly` property from the blazor.web.js options format
+  const normalizedOptions = options?.webAssembly ?? options ?? {};
+  setWebAssemblyOptions(Promise.resolve(normalizedOptions));
 
   JSEventRegistry.create(Blazor);
   const webAssemblyComponents = discoverComponents(document, 'webassembly') as WebAssemblyComponentDescriptor[];
diff --git a/src/Components/test/E2ETest/ServerExecutionTests/ServerNestedOptionsTest.cs b/src/Components/test/E2ETest/ServerExecutionTests/ServerNestedOptionsTest.cs
new file mode 100644
index 000000000000..05d9416fdac1
--- /dev/null
+++ b/src/Components/test/E2ETest/ServerExecutionTests/ServerNestedOptionsTest.cs
@@ -0,0 +1,39 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using BasicTestApp;
+using Microsoft.AspNetCore.Components.E2ETest.Infrastructure;
+using Microsoft.AspNetCore.Components.E2ETest.Infrastructure.ServerFixtures;
+using Microsoft.AspNetCore.E2ETesting;
+using OpenQA.Selenium;
+using TestServer;
+using Xunit.Abstractions;
+
+namespace Microsoft.AspNetCore.Components.E2ETest.ServerExecutionTests;
+
+public class ServerNestedOptionsTest : ServerTestBase<BasicTestAppServerSiteFixture<ServerStartup>>
+{
+    public ServerNestedOptionsTest(
+        BrowserFixture browserFixture,
+        BasicTestAppServerSiteFixture<ServerStartup> serverFixture,
+        ITestOutputHelper output)
+        : base(browserFixture, serverFixture, output)
+    {
+    }
+
+    protected override void InitializeAsyncCore()
+    {
+        Navigate($"{ServerPathBase}/nestedCircuitOptions");
+    }
+
+    [Fact]
+    public void NestedCircuitOptionsAreAccepted()
+    {
+        var appElement = Browser.MountTestComponent<CounterComponent>();
+        var countDisplayElement = appElement.FindElement(By.TagName("p"));
+        Browser.Equal("Current count: 0", () => countDisplayElement.Text);
+
+        appElement.FindElement(By.TagName("button")).Click();
+        Browser.Equal("Current count: 1", () => countDisplayElement.Text);
+    }
+}
diff --git a/src/Components/test/E2ETest/Tests/WebAssemblyNestedOptionsTest.cs b/src/Components/test/E2ETest/Tests/WebAssemblyNestedOptionsTest.cs
new file mode 100644
index 000000000000..a94df61cf823
--- /dev/null
+++ b/src/Components/test/E2ETest/Tests/WebAssemblyNestedOptionsTest.cs
@@ -0,0 +1,39 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using BasicTestApp;
+using Microsoft.AspNetCore.Components.E2ETest.Infrastructure;
+using Microsoft.AspNetCore.Components.E2ETest.Infrastructure.ServerFixtures;
+using Microsoft.AspNetCore.E2ETesting;
+using OpenQA.Selenium;
+using Xunit.Abstractions;
+
+namespace Microsoft.AspNetCore.Components.E2ETest.Tests;
+
+public class WebAssemblyNestedOptionsTest : ServerTestBase<BlazorWasmTestAppFixture<BasicTestApp.Program>>
+{
+    public WebAssemblyNestedOptionsTest(
+        BrowserFixture browserFixture,
+        BlazorWasmTestAppFixture<Program> serverFixture,
+        ITestOutputHelper output)
+        : base(browserFixture, serverFixture, output)
+    {
+        _serverFixture.PathBase = "/subdir";
+    }
+
+    protected override void InitializeAsyncCore()
+    {
+        base.InitializeAsyncCore();
+
+        // Navigate with query parameter to trigger nested options format
+        Navigate($"{ServerPathBase}?nested-options=true");
+        Browser.MountTestComponent<ConfigureRuntime>();
+    }
+
+    [Fact]
+    public void NestedWebAssemblyOptionsAreAccepted()
+    {
+        var element = Browser.Exists(By.Id("environment"));
+        Browser.Equal("true", () => element.Text);
+    }
+}
diff --git a/src/Components/test/testassets/BasicTestApp/wwwroot/index.html b/src/Components/test/testassets/BasicTestApp/wwwroot/index.html
index 9506d48c434e..3b5f3f8021f0 100644
--- a/src/Components/test/testassets/BasicTestApp/wwwroot/index.html
+++ b/src/Components/test/testassets/BasicTestApp/wwwroot/index.html
@@ -63,11 +63,25 @@
                 document.body.append(element);
             }
 
-            Blazor.start({
-                configureRuntime: dotnet => {
-                    dotnet.withEnvironmentVariable("CONFIGURE_RUNTIME", "true");
-                }
-            });
+            // Support both top-level and nested options format
+            // The nested format matches what blazor.web.js uses
+            const useNestedFormat = location.search.indexOf('nested-options=true') !== -1;
+            
+            if (useNestedFormat) {
+                Blazor.start({
+                    webAssembly: {
+                        configureRuntime: dotnet => {
+                            dotnet.withEnvironmentVariable("CONFIGURE_RUNTIME", "true");
+                        }
+                    }
+                });
+            } else {
+                Blazor.start({
+                    configureRuntime: dotnet => {
+                        dotnet.withEnvironmentVariable("CONFIGURE_RUNTIME", "true");
+                    }
+                });
+            }
         })();
     </script>
 
diff --git a/src/Components/test/testassets/Components.TestServer/Pages/NestedCircuitOptions.cshtml b/src/Components/test/testassets/Components.TestServer/Pages/NestedCircuitOptions.cshtml
new file mode 100644
index 000000000000..e05c2d7f889d
--- /dev/null
+++ b/src/Components/test/testassets/Components.TestServer/Pages/NestedCircuitOptions.cshtml
@@ -0,0 +1,33 @@
+@page "/nestedCircuitOptions"
+@addTagHelper "*, Microsoft.AspNetCore.Mvc.TagHelpers"
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8" />
+    <title>Basic test app - Nested Circuit Options</title>
+    <base href="~/" />
+    <link href="style.css" rel="stylesheet" />
+    <link rel="icon" href="data:,">
+    <component type="typeof(Microsoft.AspNetCore.Components.Web.HeadOutlet)" render-mode="Server" />
+</head>
+<body>
+    <root><component type="typeof(BasicTestApp.Index)" render-mode="Server" /></root>
+
+    <div id="blazor-error-ui">
+        An unhandled error has occurred.
+        <a href="." class="reload">Reload</a>
+        <span class="dismiss">🗙</span>
+    </div>
+
+    <script src="_framework/blazor.server.js" autostart="false"></script>
+    <script>
+        Blazor.start({
+            circuit: {
+                reconnectionOptions: {
+                    retryIntervalMilliseconds: Array.prototype.at.bind([5000, 5000, 5000, 10000, 30000]),
+                },
+            },
+        });
+    </script>
+</body>
+</html>