Use synapse API to register instead doing via UI

backend/dev_homeserver-othersite.yaml

@@ -50,6 +50,9 @@ max_event_delay_duration: 24h
 enable_registration: true
 enable_registration_without_verification: true
 
+# Shared secret for admin user registration via API (for testing only!)
+registration_shared_secret: "test_shared_secret_for_local_dev_only"
+
 report_stats: false
 serve_server_wellknown: true
 

backend/dev_homeserver.yaml

@@ -50,6 +50,9 @@ max_event_delay_duration: 24h
 enable_registration: true
 enable_registration_without_verification: true
 
+# Shared secret for admin user registration via API (for testing only!)
+registration_shared_secret: "test_shared_secret_for_local_dev_only"
+
 report_stats: false
 serve_server_wellknown: true
 

backend/dev_nginx.conf

@@ -28,11 +28,18 @@ server {
     # Reason: the lk-jwt-service uses the federation API for the openid token
     #         verification, which requires TLS
     location ~ ^(/_matrix|/_synapse/client)  {
-        proxy_pass "http://homeserver:8008";       
+        proxy_pass "http://homeserver:8008";
         proxy_http_version 1.1;
         proxy_set_header X-Forwarded-For $remote_addr;
         proxy_set_header X-Forwarded-Proto $scheme;
-        proxy_set_header Host $host;                
+        proxy_set_header Host $host;
+    }
+    location ~ ^(/_matrix|/_synapse/admin)  {
+        proxy_pass "http://homeserver:8008";
+        proxy_http_version 1.1;
+        proxy_set_header X-Forwarded-For $remote_addr;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header Host $host;
     }
 
     error_page   500 502 503 504  /50x.html;
@@ -73,7 +80,15 @@ server {
         proxy_http_version 1.1;
         proxy_set_header X-Forwarded-For $remote_addr;
         proxy_set_header X-Forwarded-Proto $scheme;
-        proxy_set_header Host $host;                
+        proxy_set_header Host $host;
+    }
+
+    location ~ ^(/_matrix|/_synapse/admin)  {
+        proxy_pass "http://homeserver-1:18008";
+        proxy_http_version 1.1;
+        proxy_set_header X-Forwarded-For $remote_addr;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header Host $host;
     }
 
     error_page   500 502 503 504  /50x.html;

backend/playwright_homeserver-othersite.yaml

@@ -50,6 +50,9 @@ max_event_delay_duration: 24h
 enable_registration: true
 enable_registration_without_verification: true
 
+# Shared secret for admin user registration via API (for testing only!)
+registration_shared_secret: "test_shared_secret_for_local_dev_only"
+
 report_stats: false
 serve_server_wellknown: true
 

backend/playwright_homeserver.yaml

@@ -50,6 +50,9 @@ max_event_delay_duration: 24h
 enable_registration: true
 enable_registration_without_verification: true
 
+# Shared secret for admin user registration via API (for testing only!)
+registration_shared_secret: "test_shared_secret_for_local_dev_only"
+
 report_stats: false
 serve_server_wellknown: true
 

playwright.config.ts

@@ -7,11 +7,22 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { defineConfig, devices } from "@playwright/test";
+import { join } from "path";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
 
 const baseURL = process.env.USE_DOCKER
   ? "http://localhost:8080"
   : "https://localhost:3000";
 
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+// Needed by the synapse admin API called in fixtures
+process.env.NODE_EXTRA_CA_CERTS = join(
+  __dirname,
+  "backend/dev_tls_local-ca.crt",
+);
+
 /**
  * See https://playwright.dev/docs/test-configuration.
  */

playwright/utils/synapse-admin.ts

@@ -0,0 +1,142 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { createHmac } from "crypto";
+
+/**
+ * Response from Synapse registration API
+ */
+export interface SynapseRegistrationResponse {
+  access_token: string;
+  user_id: string;
+  home_server: string;
+  device_id: string;
+}
+
+/**
+ * Utility class for interacting with Synapse Admin API
+ * This provides fast user registration without going through the UI
+ *
+ * @see https://matrix-org.github.io/synapse/latest/admin_api/register_api.html
+ */
+export class SynapseAdmin {
+  public constructor(
+    private baseUrl: string = "https://synapse.m.localhost",
+    private sharedSecret: string = "test_shared_secret_for_local_dev_only",
+  ) {}
+
+  /**
+   * Register a user using the Synapse Admin API
+   * This is much faster than going through the UI registration flow
+   *
+   * @param username - The username (localpart) for the new user
+   * @param password - The password for the new user
+   * @param displayName - Optional display name (defaults to username)
+   * @param admin - Whether the user should be an admin (defaults to false)
+   * @returns Registration response containing access token and user ID
+   */
+  public async registerUser(
+    username: string,
+    password: string,
+    displayName?: string,
+    admin: boolean = false,
+  ): Promise<SynapseRegistrationResponse> {
+    // Get a nonce first
+    const nonce = await this.getNonce();
+
+    // Generate the HMAC
+    const mac = this.generateMac(username, password, admin, nonce);
+
+    // Make the registration request
+    const response = await fetch(`${this.baseUrl}/_synapse/admin/v1/register`, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        nonce,
+        username,
+        password,
+        displayname: displayName || username,
+        admin,
+        mac,
+      }),
+    });
+
+    if (!response.ok) {
+      const error = await response.text();
+      throw new Error(
+        `Failed to register user ${username}: ${response.status} ${error}`,
+      );
+    }
+
+    return response.json();
+  }
+
+  /**
+   * Get a nonce for registration
+   * The nonce is required for the HMAC calculation
+   *
+   * @returns A nonce string
+   */
+  private async getNonce(): Promise<string> {
+    const response = await fetch(`${this.baseUrl}/_synapse/admin/v1/register`, {
+      method: "GET",
+    });
+
+    if (!response.ok) {
+      throw new Error(
+        `Failed to get nonce: ${response.status} ${await response.text()}`,
+      );
+    }
+
+    const data = await response.json();
+    return data.nonce;
+  }
+
+  /**
+   * Generate HMAC for shared secret registration
+   * This is the authentication mechanism for the admin API
+   *
+   * @param username - The username
+   * @param password - The password
+   * @param admin - Whether the user is an admin
+   * @param nonce - The nonce from the server
+   * @returns The HMAC hex string
+   */
+  private generateMac(
+    username: string,
+    password: string,
+    admin: boolean,
+    nonce: string,
+  ): string {
+    const mac = createHmac("sha1", this.sharedSecret);
+    mac.update(nonce);
+    mac.update("\x00");
+    mac.update(username);
+    mac.update("\x00");
+    mac.update(password);
+    mac.update("\x00");
+    mac.update(admin ? "admin" : "notadmin");
+
+    return mac.digest("hex");
+  }
+
+  /**
+   * Create a new SynapseAdmin instance for a different homeserver
+   *
+   * @param baseUrl - The base URL of the homeserver
+   * @param sharedSecret - The shared secret (defaults to test secret)
+   * @returns A new SynapseAdmin instance
+   */
+  public static forHomeserver(
+    baseUrl: string,
+    sharedSecret: string = "test_shared_secret_for_local_dev_only",
+  ): SynapseAdmin {
+    return new SynapseAdmin(baseUrl, sharedSecret);
+  }
+}

playwright/widget/test-helpers.ts

@@ -13,6 +13,8 @@ import {
 } from "@playwright/test";
 import { type MatrixClient } from "matrix-js-sdk";
 
+import { SynapseAdmin } from "../utils/synapse-admin.ts";
+
 const PASSWORD = "foobarbaz1!";
 
 export const HOST1 = "https://app.m.localhost/#/welcome";
@@ -74,29 +76,41 @@ export class TestHelpers {
     clientHandle: JSHandle<MatrixClient>;
     mxId: string;
   }> {
+    // Determine which homeserver to use based on the host
+    const synapseBaseUrl =
+      host === HOST2
+        ? "https://synapse.othersite.m.localhost"
+        : "https://synapse.m.localhost";
+
+    // Register user via Synapse Admin API to speed things up
+    const synapseAdmin = SynapseAdmin.forHomeserver(synapseBaseUrl);
+    const credentials = await synapseAdmin.registerUser(
+      username,
+      PASSWORD,
+      username,
+    );
+
+    // STEP 2: Open browser and login
     const userContext = await browser.newContext({
       reducedMotion: "reduce",
     });
     const page = await userContext.newPage();
-    await page.goto(host);
+    await page.goto(host + "/#/login");
-    await page.getByRole("link", { name: "Create Account" }).click();
+
+    await page.getByRole("link", { name: "Sign in" }).click();
+
     await page.getByRole("textbox", { name: "Username" }).fill(username);
-    await page.getByRole("textbox", { name: "Password", exact: true }).click();
+    await page.getByRole("textbox", { name: "Password" }).fill(PASSWORD);
-    await page
+    await page.getByRole("button", { name: "Sign in" }).click();
-      .getByRole("textbox", { name: "Password", exact: true })
+
-      .fill(PASSWORD);
+    // 😤For reasons web is staying on an infinite loading page after login, so we reload the page
-    await page.getByRole("textbox", { name: "Confirm password" }).click();
+    // Super annoying to have to wait...
-    await page
+    await page.waitForTimeout(2000);
-      .getByRole("textbox", { name: "Confirm password" })
+    await page.reload();
-      .fill(PASSWORD);
-    await page.getByRole("button", { name: "Register" }).click();
 
     await expect(
       page.getByRole("heading", { name: `Welcome ${username}` }),
-    ).toBeVisible({
+    ).toBeVisible();
-      // Increase timeout as registration can be slow :/
-      timeout: 15_000,
-    });
 
     await this.maybeDismissBrowserNotSupportedToast(page);
     await this.maybeDismissServiceWorkerWarningToast(page);
@@ -106,11 +120,7 @@ export class TestHelpers {
     const clientHandle = await page.evaluateHandle(() =>
       window.mxMatrixClientPeg.get(),
     );
-    const mxId = (await clientHandle.evaluate(
+    const mxId = credentials.user_id;
-      (cli: MatrixClient) => cli.getUserId(),
-      clientHandle,
-    ))!;
-
     return { page, clientHandle, mxId };
   }