diff --git a/src/Components/Web.JS/dist/Release/blazor.webassembly.js b/src/Components/Web.JS/dist/Release/blazor.webassembly.js
index 578dbea90e4a28d2e08b6cab050c13777ce8b23d..f4eeebb6339762a6cd6ba7788a32d084e5b2c296 100644
Binary files a/src/Components/Web.JS/dist/Release/blazor.webassembly.js and b/src/Components/Web.JS/dist/Release/blazor.webassembly.js differ
diff --git a/src/Components/Web.JS/src/Boot.WebAssembly.ts b/src/Components/Web.JS/src/Boot.WebAssembly.ts
index 99b117ad78d50305a8571622f80946aca3f81409..b0e4546681e45ebdadcbf828c1c7226e91d36e3f 100644
--- a/src/Components/Web.JS/src/Boot.WebAssembly.ts
+++ b/src/Components/Web.JS/src/Boot.WebAssembly.ts
@@ -66,8 +66,11 @@ async function boot(options?: Partial<WebAssemblyStartOptions>): Promise<void> {
     );
   });
 
+  // Get the custom environment setting if defined
+  const environment = options?.environment;
+
   // Fetch the resources and prepare the Mono runtime
-  const bootConfigResult = await BootConfigResult.initAsync();
+  const bootConfigResult = await BootConfigResult.initAsync(environment);
 
   const [resourceLoader] = await Promise.all([
     WebAssemblyResourceLoader.initAsync(bootConfigResult.bootConfig, options || {}),
diff --git a/src/Components/Web.JS/src/Platform/BootConfig.ts b/src/Components/Web.JS/src/Platform/BootConfig.ts
index fbf88ef0925dac3da5d941119370f3f4459cf579..5ff23f860f8a06b247cbbad9092cd7ed060d6556 100644
--- a/src/Components/Web.JS/src/Platform/BootConfig.ts
+++ b/src/Components/Web.JS/src/Platform/BootConfig.ts
@@ -2,7 +2,7 @@ export class BootConfigResult {
   private constructor(public bootConfig: BootJsonData, public applicationEnvironment: string) {
   }
 
-  static async initAsync(): Promise<BootConfigResult> {
+  static async initAsync(environment?: string): Promise<BootConfigResult> {
     const bootConfigResponse = await fetch('_framework/blazor.boot.json', {
       method: 'GET',
       credentials: 'include',
@@ -10,8 +10,8 @@ export class BootConfigResult {
     });
 
     // While we can expect an ASP.NET Core hosted application to include the environment, other
-    // hosts may not. Assume 'Production' in the absenc of any specified value.
-    const applicationEnvironment = bootConfigResponse.headers.get('Blazor-Environment') || 'Production';
+    // hosts may not. Assume 'Production' in the absence of any specified value.
+    const applicationEnvironment = environment || bootConfigResponse.headers.get('Blazor-Environment') || 'Production';
     const bootConfig: BootJsonData = await bootConfigResponse.json();
 
     return new BootConfigResult(bootConfig, applicationEnvironment);
diff --git a/src/Components/Web.JS/src/Platform/WebAssemblyStartOptions.ts b/src/Components/Web.JS/src/Platform/WebAssemblyStartOptions.ts
index c6710e74059f626e5b5dfc234f8b55f5988e3761..5c3dee8692cf76e724f5d3a48e0d2e4a5200deb0 100644
--- a/src/Components/Web.JS/src/Platform/WebAssemblyStartOptions.ts
+++ b/src/Components/Web.JS/src/Platform/WebAssemblyStartOptions.ts
@@ -9,6 +9,11 @@ export interface WebAssemblyStartOptions {
    * @returns A URI string or a Response promise to override the loading process, or null/undefined to allow the default loading behavior.
    */
   loadBootResource(type: WebAssemblyBootResourceType, name: string, defaultUri: string, integrity: string) : string | Promise<Response> | null | undefined;
+
+  /**
+   * Override built-in environment setting on start.
+   */
+  environment?: string;
 }
 
 // This type doesn't have to align with anything in BootConfig.