diff --git a/packages/cli/src/lib/execute-route-module.js b/packages/cli/src/lib/execute-route-module.js
index 483696fdc..1d3746ace 100644
--- a/packages/cli/src/lib/execute-route-module.js
+++ b/packages/cli/src/lib/execute-route-module.js
@@ -15,7 +15,7 @@ async function executeRouteModule({ moduleUrl, compilation, page = {}, prerender
     data.html = html;
   } else {
     const module = await import(moduleUrl).then(module => module);
-    const { prerender = false, getTemplate = null, getBody = null, getFrontmatter = null } = module;
+    const { prerender = false, getTemplate = null, getBody = null, getFrontmatter = null, isolation } = module;
 
     if (module.default) {
       const { html } = await renderToString(new URL(moduleUrl), false, request);
@@ -35,7 +35,10 @@ async function executeRouteModule({ moduleUrl, compilation, page = {}, prerender
       data.frontmatter = await getFrontmatter(compilation, page);
     }
 
+    // TODO cant we get these from just pulling from the file during the graph phase?
+    // https://github.com/ProjectEvergreen/greenwood/issues/991
     data.prerender = prerender;
+    data.isolation = isolation;
   }
 
   return data;
diff --git a/packages/cli/src/lib/ssr-route-worker-isolation-mode.js b/packages/cli/src/lib/ssr-route-worker-isolation-mode.js
new file mode 100644
index 000000000..831fa8e71
--- /dev/null
+++ b/packages/cli/src/lib/ssr-route-worker-isolation-mode.js
@@ -0,0 +1,14 @@
+// https://github.com/nodejs/modules/issues/307#issuecomment-858729422
+import { parentPort } from 'worker_threads';
+
+async function executeModule({ routeModuleUrl, request, compilation }) {
+  const { handler } = await import(routeModuleUrl);
+  const response = await handler(request, compilation);
+  const html = await response.text();
+
+  parentPort.postMessage(html);
+}
+
+parentPort.on('message', async (task) => {
+  await executeModule(task);
+});
\ No newline at end of file
diff --git a/packages/cli/src/lifecycles/config.js b/packages/cli/src/lifecycles/config.js
index e9b9dd400..e15fcc998 100644
--- a/packages/cli/src/lifecycles/config.js
+++ b/packages/cli/src/lifecycles/config.js
@@ -50,6 +50,7 @@ const defaultConfig = {
   plugins: greenwoodPlugins,
   markdown: { plugins: [], settings: {} },
   prerender: false,
+  isolation: false,
   pagesDirectory: 'pages',
   templatesDirectory: 'templates'
 };
@@ -76,7 +77,7 @@ const readAndMergeConfig = async() => {
 
       if (hasConfigFile) {
         const userCfgFile = (await import(configUrl)).default;
-        const { workspace, devServer, markdown, optimization, plugins, port, prerender, basePath, staticRouter, pagesDirectory, templatesDirectory, interpolateFrontmatter } = userCfgFile;
+        const { workspace, devServer, markdown, optimization, plugins, port, prerender, basePath, staticRouter, pagesDirectory, templatesDirectory, interpolateFrontmatter, isolation } = userCfgFile;
 
         // workspace validation
         if (workspace) {
@@ -223,6 +224,14 @@ const readAndMergeConfig = async() => {
           customConfig.prerender = false;
         }
 
+        if (isolation !== undefined) {
+          if (typeof isolation === 'boolean') {
+            customConfig.isolation = isolation;
+          } else {
+            reject(`Error: greenwood.config.js isolation must be a boolean; true or false.  Passed value was typeof: ${typeof staticRouter}`);
+          }
+        }
+
         if (staticRouter !== undefined) {
           if (typeof staticRouter === 'boolean') {
             customConfig.staticRouter = staticRouter;
diff --git a/packages/cli/src/lifecycles/graph.js b/packages/cli/src/lifecycles/graph.js
index ae82285e6..557d6c0f9 100644
--- a/packages/cli/src/lifecycles/graph.js
+++ b/packages/cli/src/lifecycles/graph.js
@@ -22,7 +22,8 @@ const generateGraph = async (compilation) => {
         data: {},
         imports: [],
         resources: [],
-        prerender: true
+        prerender: true,
+        isolation: false
       }];
 
       const walkDirectoryForPages = async function(directory, pages = []) {
@@ -49,6 +50,7 @@ const generateGraph = async (compilation) => {
             let customData = {};
             let filePath;
             let prerender = true;
+            let isolation = false;
 
             /*
              * check if additional nested directories exist to correctly determine route (minus filename)
@@ -131,6 +133,7 @@ const generateGraph = async (compilation) => {
 
                 worker.on('message', async (result) => {
                   prerender = result.prerender;
+                  isolation = result.isolation ?? isolation;
 
                   if (result.frontmatter) {
                     result.frontmatter.imports = result.frontmatter.imports || [];
@@ -201,6 +204,7 @@ const generateGraph = async (compilation) => {
              * title: a default value that can be used for <title></title>
              * isSSR: if this is a server side route
              * prerednder: if this should be statically exported
+             * isolation: if this should be run in isolated mode
              */
             pages.push({
               data: customData || {},
@@ -220,7 +224,8 @@ const generateGraph = async (compilation) => {
               template,
               title,
               isSSR: !isStatic,
-              prerender
+              prerender,
+              isolation
             });
           }
         }
@@ -240,27 +245,34 @@ const generateGraph = async (compilation) => {
             apis = await walkDirectoryForApis(filenameUrlAsDir, apis);
           } else {
             const extension = filenameUrl.pathname.split('.').pop();
-            const relativeApiPath = filenameUrl.pathname.replace(userWorkspace.pathname, '/');
-            const route = `${basePath}${relativeApiPath.replace(`.${extension}`, '')}`;
 
             if (extension !== 'js') {
               console.warn(`${filenameUrl} is not a JavaScript file, skipping...`);
-            } else {
-              /*
-              * API Properties (per route)
-              *----------------------
-              * filename: base filename of the page
-              * outputPath: the filename to write to when generating a build
-              * path: path to the file relative to the workspace
-              * route: URL route for a given page on outputFilePath
-              */
-              apis.set(route, {
-                filename: filename,
-                outputPath: `/api/${filename}`,
-                path: relativeApiPath,
-                route
-              });
+              return;
             }
+
+            const relativeApiPath = filenameUrl.pathname.replace(userWorkspace.pathname, '/');
+            const route = `${basePath}${relativeApiPath.replace(`.${extension}`, '')}`;
+            // TODO should this be run in isolation like SSR pages?
+            // https://github.com/ProjectEvergreen/greenwood/issues/991
+            const { isolation } = await import(filenameUrl).then(module => module);
+
+            /*
+            * API Properties (per route)
+            *----------------------
+            * filename: base filename of the page
+            * outputPath: the filename to write to when generating a build
+            * path: path to the file relative to the workspace
+            * route: URL route for a given page on outputFilePath
+            * isolation: if this should be run in isolated mode
+            */
+            apis.set(route, {
+              filename: filename,
+              outputPath: `/api/${filename}`,
+              path: relativeApiPath,
+              route,
+              isolation
+            });
           }
         }
 
diff --git a/packages/cli/src/lifecycles/serve.js b/packages/cli/src/lifecycles/serve.js
index 678750374..903af038c 100644
--- a/packages/cli/src/lifecycles/serve.js
+++ b/packages/cli/src/lifecycles/serve.js
@@ -2,9 +2,10 @@ import fs from 'fs/promises';
 import { hashString } from '../lib/hashing-utils.js';
 import Koa from 'koa';
 import { koaBody } from 'koa-body';
-import { checkResourceExists, mergeResponse, transformKoaRequestIntoStandardRequest } from '../lib/resource-utils.js';
+import { checkResourceExists, mergeResponse, transformKoaRequestIntoStandardRequest, requestAsObject } from '../lib/resource-utils.js';
 import { Readable } from 'stream';
 import { ResourceInterface } from '../lib/resource-interface.js';
+import { Worker } from 'worker_threads';
 
 async function getDevServer(compilation) {
   const app = new Koa();
@@ -282,6 +283,7 @@ async function getStaticServer(compilation, composable) {
 async function getHybridServer(compilation) {
   const { graph, manifest, context, config } = compilation;
   const { outputDir } = context;
+  const isolationMode = config.isolation;
   const app = await getStaticServer(compilation, true);
 
   app.use(koaBody());
@@ -294,17 +296,83 @@ async function getHybridServer(compilation) {
       const request = transformKoaRequestIntoStandardRequest(url, ctx.request);
 
       if (!config.prerender && matchingRoute.isSSR && !matchingRoute.prerender) {
-        const { handler } = await import(new URL(`./__${matchingRoute.filename}`, outputDir));
-        const response = await handler(request, compilation);
+        let html;
+
+        if (matchingRoute.isolation || isolationMode) {
+          await new Promise(async (resolve, reject) => {
+            const worker = new Worker(new URL('../lib/ssr-route-worker-isolation-mode.js', import.meta.url));
+            // TODO "faux" new Request here, a better way?
+            const request = await requestAsObject(new Request(url));
+
+            worker.on('message', async (result) => {
+              html = result;
+
+              resolve();
+            });
+            worker.on('error', reject);
+            worker.on('exit', (code) => {
+              if (code !== 0) {
+                reject(new Error(`Worker stopped with exit code ${code}`));
+              }
+            });
+
+            worker.postMessage({
+              routeModuleUrl: new URL(`./__${matchingRoute.filename}`, outputDir).href,
+              request,
+              compilation: JSON.stringify(compilation)
+            });
+          });
+        } else {
+          const { handler } = await import(new URL(`./__${matchingRoute.filename}`, outputDir));
+          const response = await handler(request, compilation);
 
-        ctx.body = Readable.from(response.body);
+          html = Readable.from(response.body);
+        }
+
+        ctx.body = html;
         ctx.set('Content-Type', 'text/html');
         ctx.status = 200;
       } else if (isApiRoute) {
         const apiRoute = manifest.apis.get(url.pathname);
-        const { handler } = await import(new URL(`.${apiRoute.path}`, outputDir));
-        const response = await handler(request);
-        const { body, status, headers, statusText } = response;
+        let body, status, headers, statusText;
+
+        if (apiRoute.isolation || isolationMode) {
+          await new Promise(async (resolve, reject) => {
+            const worker = new Worker(new URL('../lib/api-route-worker.js', import.meta.url));
+            // TODO "faux" new Request here, a better way?
+            const req = await requestAsObject(request);
+
+            worker.on('message', async (result) => {
+              const responseAsObject = result;
+
+              body = responseAsObject.body;
+              status = responseAsObject.status;
+              headers = new Headers(responseAsObject.headers);
+              statusText = responseAsObject.statusText;
+
+              resolve();
+            });
+            worker.on('error', reject);
+            worker.on('exit', (code) => {
+              if (code !== 0) {
+                reject(new Error(`Worker stopped with exit code ${code}`));
+              }
+            });
+
+            worker.postMessage({
+              href: new URL(`.${apiRoute.path}`, outputDir).href,
+              request: req
+            });
+          });
+        } else {
+          const { handler } = await import(new URL(`.${apiRoute.path}`, outputDir));
+          const response = await handler(request);
+
+          body = response.body;
+          status = response.status;
+          headers = response.headers;
+          statusText = response.statusText;
+        }
 
         ctx.body = body ? Readable.from(body) : null;
         ctx.status = status;
diff --git a/packages/cli/test/cases/build.config.error-isolation/build.config.error-isolation.spec.js b/packages/cli/test/cases/build.config.error-isolation/build.config.error-isolation.spec.js
new file mode 100644
index 000000000..b262cc677
--- /dev/null
+++ b/packages/cli/test/cases/build.config.error-isolation/build.config.error-isolation.spec.js
@@ -0,0 +1,49 @@
+/*
+ * Use Case
+ * Run Greenwood build command with a bad value for isolation mode in a custom config.
+ *
+ * User Result
+ * Should throw an error.
+ *
+ * User Command
+ * greenwood build
+ *
+ * User Config
+ * {
+ *   isolation: {}
+ * }
+ *
+ * User Workspace
+ * Greenwood default
+ */
+import chai from 'chai';
+import path from 'path';
+import { Runner } from 'gallinago';
+import { fileURLToPath, URL } from 'url';
+
+const expect = chai.expect;
+
+describe('Build Greenwood With: ', function() {
+  const cliPath = path.join(process.cwd(), 'packages/cli/src/index.js');
+  const outputPath = fileURLToPath(new URL('.', import.meta.url));
+  let runner;
+
+  before(function() {
+    this.context = {
+      publicDir: path.join(outputPath, 'public')
+    };
+    runner = new Runner();
+  });
+
+  describe('Custom Configuration with a bad value for Isolation', function() {
+    it('should throw an error that isolation must be a boolean', function() {
+      try {
+        runner.setup(outputPath);
+        runner.runCommand(cliPath, 'build');
+      } catch (err) {
+        expect(err).to.contain('Error: greenwood.config.js isolation must be a boolean; true or false.  Passed value was typeof: object');
+      }
+    });
+  });
+
+});
\ No newline at end of file
diff --git a/packages/cli/test/cases/build.config.error-isolation/greenwood.config.js b/packages/cli/test/cases/build.config.error-isolation/greenwood.config.js
new file mode 100644
index 000000000..211201604
--- /dev/null
+++ b/packages/cli/test/cases/build.config.error-isolation/greenwood.config.js
@@ -0,0 +1,3 @@
+export default {
+  isolation: {}
+};
\ No newline at end of file
diff --git a/packages/cli/test/cases/serve.default.api/serve.default.api.spec.js b/packages/cli/test/cases/serve.default.api/serve.default.api.spec.js
index 3baa2e383..979721912 100644
--- a/packages/cli/test/cases/serve.default.api/serve.default.api.spec.js
+++ b/packages/cli/test/cases/serve.default.api/serve.default.api.spec.js
@@ -14,7 +14,7 @@
  * User Workspace
  * src/
  *   api/
- *     fragment.js
+ *     fragment.js (isolation mode)
  *     greeting.js
  *     missing.js
  *     nothing.js
diff --git a/packages/cli/test/cases/serve.default.api/src/api/fragment.js b/packages/cli/test/cases/serve.default.api/src/api/fragment.js
index ab5a5722c..992d3dd91 100644
--- a/packages/cli/test/cases/serve.default.api/src/api/fragment.js
+++ b/packages/cli/test/cases/serve.default.api/src/api/fragment.js
@@ -1,5 +1,7 @@
 import { renderFromHTML } from 'wc-compiler';
 
+export const isolation = true;
+
 export async function handler(request) {
   const params = new URLSearchParams(request.url.slice(request.url.indexOf('?')));
   const name = params.has('name') ? params.get('name') : 'World';
diff --git a/packages/cli/test/cases/serve.default.ssr/serve.default.ssr.spec.js b/packages/cli/test/cases/serve.default.ssr/serve.default.ssr.spec.js
index 7368eb07b..d19428e48 100644
--- a/packages/cli/test/cases/serve.default.ssr/serve.default.ssr.spec.js
+++ b/packages/cli/test/cases/serve.default.ssr/serve.default.ssr.spec.js
@@ -25,7 +25,7 @@
  *     artists.js
  *     index.js
  *     post.js
- *     users.js
+ *     users.js (isolation = true)
  *   templates/
  *     app.html
  */
diff --git a/packages/cli/test/cases/serve.default.ssr/src/pages/users.js b/packages/cli/test/cases/serve.default.ssr/src/pages/users.js
index f2eeafaf3..71a468f33 100644
--- a/packages/cli/test/cases/serve.default.ssr/src/pages/users.js
+++ b/packages/cli/test/cases/serve.default.ssr/src/pages/users.js
@@ -17,4 +17,6 @@ export default class UsersPage extends HTMLElement {
       ${html}
     `;
   }
-}
\ No newline at end of file
+}
+
+export const isolation = true;
\ No newline at end of file
diff --git a/packages/plugin-renderer-lit/README.md b/packages/plugin-renderer-lit/README.md
index 0bdae3e78..7fa2b6f2e 100644
--- a/packages/plugin-renderer-lit/README.md
+++ b/packages/plugin-renderer-lit/README.md
@@ -88,6 +88,8 @@ customElements.define('artists-page', ArtistsPage);
 export const tagName = 'artists-page';
 ```
 
+> _By default, this plugin sets `isolation` mode to `true` for all SSR pages.  See the [isolation configuration](https://www.greenwoodjs.io/docs/configuration/#isolation) docs for more information._
+
 ## Caveats
 
 There are a few considerations to take into account when using a `LitElement` as your page component:
diff --git a/packages/plugin-renderer-lit/src/execute-route-module.js b/packages/plugin-renderer-lit/src/execute-route-module.js
index 5e73f7505..10a7d0149 100644
--- a/packages/plugin-renderer-lit/src/execute-route-module.js
+++ b/packages/plugin-renderer-lit/src/execute-route-module.js
@@ -38,7 +38,13 @@ async function executeRouteModule({ moduleUrl, compilation, page, prerender, htm
     data.html = await getTemplateResultString(templateResult);
   } else {
     const module = await import(moduleUrl).then(module => module);
-    const { getTemplate = null, getBody = null, getFrontmatter = null } = module;
+    const { getTemplate = null, getBody = null, getFrontmatter = null, isolation = true } = module;
+
+    // TODO cant we get these from just pulling from the file during the graph phase?
+    // https://github.com/ProjectEvergreen/greenwood/issues/991
+    if (isolation) {
+      data.isolation = true;
+    }
 
     if (module.default && module.tagName) {
       const { tagName } = module;
diff --git a/packages/plugin-renderer-lit/test/cases/serve.default/serve.default.spec.js b/packages/plugin-renderer-lit/test/cases/serve.default/serve.default.spec.js
index b36cf230d..2f776bc7c 100644
--- a/packages/plugin-renderer-lit/test/cases/serve.default/serve.default.spec.js
+++ b/packages/plugin-renderer-lit/test/cases/serve.default/serve.default.spec.js
@@ -19,7 +19,7 @@
  *     greeting.js
  *   pages/
  *     artists.js
- *     users.js
+ *     users.js (isolation = false)
  *   templates/
  *     app.html
  */
diff --git a/packages/plugin-renderer-lit/test/cases/serve.default/src/pages/users.js b/packages/plugin-renderer-lit/test/cases/serve.default/src/pages/users.js
index f6fe81ebf..71a9515e5 100644
--- a/packages/plugin-renderer-lit/test/cases/serve.default/src/pages/users.js
+++ b/packages/plugin-renderer-lit/test/cases/serve.default/src/pages/users.js
@@ -20,5 +20,6 @@ class UsersComponent extends LitElement {
 
 customElements.define('app-users', UsersComponent);
 
+export const isolation = false;
 export const tagName = 'app-users';
 export default UsersComponent;
\ No newline at end of file
diff --git a/www/pages/docs/api-routes.md b/www/pages/docs/api-routes.md
index 4e248c192..b05f28d8e 100644
--- a/www/pages/docs/api-routes.md
+++ b/www/pages/docs/api-routes.md
@@ -75,4 +75,14 @@ export async function handler(request) {
 
   return new Response(html, { headers });
 }
-```
\ No newline at end of file
+```
+
+### Isolation
+
+To execute an API route in its own request context when running `greenwood serve`, you can export an `isolation` option from your page set to `true`.
+
+```js
+export const isolation = true;
+```
+
+> For more information and how you can enable this for all pages, please see the [isolation configuration](/docs/configuration/#isolation) docs.
\ No newline at end of file
diff --git a/www/pages/docs/configuration.md b/www/pages/docs/configuration.md
index 1575d5013..177cb1d47 100644
--- a/www/pages/docs/configuration.md
+++ b/www/pages/docs/configuration.md
@@ -31,7 +31,8 @@ export default {
   plugins: [],
   workspace: new URL('./src/', import.meta.url),
   pagesDirectory: 'pages', // e.g. src/pages
-  templatesDirectory: 'templates' // e.g. src/templates
+  templatesDirectory: 'templates', // e.g. src/templates
+  isolation: false
 };
 ```
 
@@ -127,6 +128,36 @@ Lorum Ipsum.
 </html>
 ```
 
+### Isolation Mode
+
+If running Greenwood as a server in production with the `greenwood serve` command, it may be desirable to isolate the server rendering of SSR pages and API routes from the global runtime (e.g. NodeJS) process.  This is a common assumption for many Web Component libraries that may aim to more faithfully honor the browser's native specification on the server.
+
+Examples include:
+- Custom Elements Registry - Per the spec, a custom element can only be defined once using `customElements.define`.
+- DOM Shims - These often assume a globally unique runtime, and so issues can arise when these DOM globals are repeatedly loaded and initialized into the global space
+
+> See these discussions for more information
+> - https://github.com/ProjectEvergreen/greenwood/discussions/1117
+> - https://github.com/ProjectEvergreen/wcc/discussions/145
+
+As servers have to support multiple clients (as opposed to a browser tab only serving one client at a time), Greenwood offers an isolation mode that can be used to run SSR pages and API routes in their own context per request.
+
+#### Example
+
+To configure an entire project for this, simply set the flag in your _greenwood.config.js_
+```js
+export default {
+  isolation: true // default value is false
+};
+```
+
+Optionally, you can opt-in on a per SSR page / API route basis by exporting an `isolation` option.
+```js
+// src/pages/products.js
+
+export const isolation = true;
+``` 
+
 ### Markdown
 You can install and provide custom **unifiedjs** [presets](https://github.com/unifiedjs/unified#preset) and [plugins](https://github.com/unifiedjs/unified#plugin) to further customize and process your markdown past what [Greenwood does by default](https://github.com/ProjectEvergreen/greenwood/blob/release/0.10.0/packages/cli/src/transforms/transform.md.js#L68).  After running an `npm install` you can provide their package names to Greenwood.
 
diff --git a/www/pages/docs/server-rendering.md b/www/pages/docs/server-rendering.md
index ca94e015e..411cc06fe 100644
--- a/www/pages/docs/server-rendering.md
+++ b/www/pages/docs/server-rendering.md
@@ -225,6 +225,17 @@ export const prerender = true;
 
 > You can enable this for all pages using the [prerender configuration](/docs/configuration/#prerender) option.
 
+### Isolation
+
+To execute an SSR page in its own request context when running `greenwood serve`, you can export an `isolation` option from your page set to `true`.
+
+```js
+export const isolation = true;
+```
+
+> For more information and how you can enable this for all pages, please see the [isolation configuration](/docs/configuration/#isolation) docs.
+
+
 ### Custom Imports
 
 > ⚠️ _This feature is experimental._