diff --git a/projects/core/router/url/index.test.ts b/projects/core/router/url/index.test.ts
index 9ded952d..62ff3801 100644
--- a/projects/core/router/url/index.test.ts
+++ b/projects/core/router/url/index.test.ts
@@ -1,7 +1,8 @@
-import { Component } from '@angular/core';
+import { Component, REQUEST } from '@angular/core';
 import { TestBed } from '@angular/core/testing';
 import { NavigationEnd, Router } from '@angular/router';
 import { Subject } from 'rxjs';
+import { IS_BROWSER, IS_SERVER } from '@signality/core/internal';
 import { url } from './index';
 
 describe(url.name, () => {
@@ -118,4 +119,83 @@ describe(url.name, () => {
       expect(component.absoluteUrl()).toBe('http://localhost:4200/dashboard');
     });
   });
+
+  describe('server rendering', () => {
+    @Component({ template: '{{ relativeUrl() }}|{{ absoluteUrl() }}' })
+    class TestComponent {
+      readonly relativeUrl = url();
+      readonly absoluteUrl = url({ absolute: true });
+    }
+
+    const configureServer = (request: Request | null) => {
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [
+          { provide: Router, useValue: mockRouter },
+          { provide: IS_SERVER, useValue: true },
+          { provide: IS_BROWSER, useValue: false },
+          { provide: REQUEST, useValue: request },
+        ],
+      });
+    };
+
+    const createComponent = () => {
+      const fixture = TestBed.createComponent(TestComponent);
+      fixture.detectChanges();
+      return fixture.componentInstance;
+    };
+
+    it('should prepend the request origin to an absolute URL', () => {
+      configureServer(new Request('https://example.com/home'));
+
+      const component = createComponent();
+
+      expect(component.relativeUrl()).toBe('/home');
+      expect(component.absoluteUrl()).toBe('https://example.com/home');
+    });
+
+    it('should take only the origin from the request and the path from the router', () => {
+      mockRouter.url = '/products/123?sort=name';
+      configureServer(new Request('https://example.com:8443/redirected'));
+
+      const component = createComponent();
+
+      expect(component.absoluteUrl()).toBe('https://example.com:8443/products/123?sort=name');
+    });
+
+    it('should fall back to a relative URL and warn when there is no request', () => {
+      const warn = jest.spyOn(console, 'warn').mockImplementation(() => undefined);
+      configureServer(null);
+
+      const component = createComponent();
+
+      expect(component.absoluteUrl()).toBe('/home');
+      expect(warn).toHaveBeenCalledWith(expect.stringContaining('[url]'));
+    });
+
+    it('should not warn when `absolute` is not requested', () => {
+      const warn = jest.spyOn(console, 'warn').mockImplementation(() => undefined);
+
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [
+          { provide: Router, useValue: mockRouter },
+          { provide: IS_SERVER, useValue: true },
+          { provide: IS_BROWSER, useValue: false },
+          { provide: REQUEST, useValue: null },
+        ],
+      });
+
+      @Component({ template: '{{ relativeUrl() }}' })
+      class RelativeOnly {
+        readonly relativeUrl = url();
+      }
+
+      const fixture = TestBed.createComponent(RelativeOnly);
+      fixture.detectChanges();
+
+      expect(fixture.componentInstance.relativeUrl()).toBe('/home');
+      expect(warn).not.toHaveBeenCalled();
+    });
+  });
 });
diff --git a/projects/core/router/url/index.ts b/projects/core/router/url/index.ts
index 433dedce..42f62e00 100644
--- a/projects/core/router/url/index.ts
+++ b/projects/core/router/url/index.ts
@@ -1,4 +1,4 @@
-import { type CreateSignalOptions, inject, signal, type Signal } from '@angular/core';
+import { type CreateSignalOptions, inject, REQUEST, signal, type Signal } from '@angular/core';
 import { Router } from '@angular/router';
 import { constSignal, setupContext } from '@signality/core/internal';
 import type { WithInjector } from '@signality/core/types';
@@ -7,6 +7,10 @@ import { routerListener } from '@signality/core/router/router-listener';
 export interface UrlOptions extends CreateSignalOptions<string>, WithInjector {
   /**
    * Include origin (protocol + host) for absolute URL.
+   *
+   * On the server the origin comes from the `REQUEST` token. While prerendering there is no
+   * request, so the origin is unknown and the signal falls back to a relative URL.
+   *
    * @default false
    */
   readonly absolute?: boolean;
@@ -41,7 +45,24 @@ export function url(options?: UrlOptions): Signal<string> {
     const router = inject(Router);
 
     if (isServer) {
-      return constSignal(router.url);
+      const relativeUrl = router.url;
+
+      if (!options?.absolute) {
+        return constSignal(relativeUrl);
+      }
+
+      const request = inject(REQUEST, { optional: true });
+      if (!request) {
+        if (ngDevMode) {
+          console.warn(
+            '[url] `absolute` is ignored while prerendering, because the deployment origin is unknown at build time. Falling back to a relative URL.'
+          );
+        }
+
+        return constSignal(relativeUrl);
+      }
+
+      return constSignal(new URL(request.url).origin + relativeUrl);
     }
 
     const getUrl = () => {
diff --git a/projects/docs/router/url.md b/projects/docs/router/url.md
index 79205d6d..4091b2e0 100644
--- a/projects/docs/router/url.md
+++ b/projects/docs/router/url.md
@@ -91,6 +91,10 @@ export class ShareButtons {
 
 On the server, the signal initializes with the current URL from the router's [`url`](https://angular.dev/api/router/Router#url) property.
 
+With `absolute: true`, the origin is taken from the [`REQUEST`](https://angular.dev/api/core/REQUEST) token, so the rendered value matches the origin the visitor actually requested — including behind a reverse proxy that terminates TLS (`X-Forwarded-Host` and `X-Forwarded-Proto` are honoured).
+
+During **prerendering** there is no request, and therefore no origin: the deployment host is not knowable at build time. The signal falls back to a relative URL and logs a warning in development builds. Keep this in mind when using `absolute: true` for crawler-visible metadata such as `og:url` — a prerendered page will carry a relative value until it is hydrated.
+
 ## Type Definitions
 
 ```typescript