diff --git a/backend/src/api-tests/sso.test.ts b/backend/src/api-tests/sso.test.ts
index 69bfae13..b64a3ce1 100644
--- a/backend/src/api-tests/sso.test.ts
+++ b/backend/src/api-tests/sso.test.ts
@@ -53,3 +53,46 @@ describe('/api/sso/service', () => {
       .expect(200);
   });
 });
+
+describe('/api/sso/public', () => {
+  const APP = testServerRunner(async () => ({
+    run: await appFactory(
+      testConfig({
+        insecure: {
+          sharedAccount: { enabled: true, authUrl: '/insecure-login' },
+        },
+      }),
+    ),
+  }));
+
+  it('returns a signed JWT token with the user ID', async (props) => {
+    const { server } = props.getTyped(APP);
+
+    const response1 = await request(server)
+      .get('/insecure-login?redirect_uri=http://example.com/&state={}')
+      .expect(303);
+
+    const url = new URL(response1.headers['location']!);
+    expect(url.host).toEqual('example.com');
+    const urlParams = new URLSearchParams(url.hash.substring(1));
+    const externalToken = urlParams.get('token')!;
+    expect(externalToken.length).toBeGreaterThan(10);
+
+    const response2 = await request(server)
+      .post('/api/sso/public')
+      .send({ externalToken })
+      .expect(200);
+
+    const { userToken } = response2.body;
+    const data = jwt.decode(userToken, '', true);
+
+    expect(data.aud).toEqual('user');
+    expect(data.sub).toEqual('everybody');
+    expect(data.iss).toEqual('public');
+
+    await request(server)
+      .get('/api/retros')
+      .set('Authorization', `Bearer ${userToken}`)
+      .expect(200);
+  });
+});
diff --git a/backend/src/api-tests/testConfig.ts b/backend/src/api-tests/testConfig.ts
index 3482dbc4..462eaf66 100644
--- a/backend/src/api-tests/testConfig.ts
+++ b/backend/src/api-tests/testConfig.ts
@@ -20,6 +20,12 @@ const baseTestConfig: ConfigT = {
   token: { secretPassphrase: '' },
   encryption: { secretKey: '' },
   db: { url: 'memory://' },
+  insecure: {
+    sharedAccount: {
+      enabled: false,
+      authUrl: '/insecure-login',
+    },
+  },
   sso: {
     google: { clientId: '', authUrl: '', tokenInfoUrl: '' },
     github: {
diff --git a/backend/src/app.ts b/backend/src/app.ts
index 265341d2..391c3502 100644
--- a/backend/src/app.ts
+++ b/backend/src/app.ts
@@ -2,7 +2,6 @@ import { join } from 'node:path';
 import { WebSocketExpress } from 'websocket-express';
 import { connectDB } from './import-wrappers/collection-storage-wrap';
 import { Hasher } from 'pwd-hasher';
-import ab from 'authentication-backend';
 import { ApiConfigRouter } from './routers/ApiConfigRouter';
 import { ApiAuthRouter } from './routers/ApiAuthRouter';
 import { ApiSlugsRouter } from './routers/ApiSlugsRouter';
@@ -18,8 +17,14 @@ import { RetroService } from './services/RetroService';
 import { RetroArchiveService } from './services/RetroArchiveService';
 import { RetroAuthService } from './services/RetroAuthService';
 import { UserAuthService } from './services/UserAuthService';
+import { getAuthBackend } from './auth';
 import { type ConfigT } from './config';
 import { basedir } from './basedir';
+import {
+  addNoCacheHeaders,
+  addSecurityHeaders,
+  removeHtmlSecurityHeaders,
+} from './headers';
 
 export interface TestHooks {
   retroService: RetroService;
@@ -37,53 +42,6 @@ export class App {
   ) {}
 }
 
-const devMode = process.env['NODE_ENV'] === 'development';
-
-const CSP_DOMAIN_PLACEHOLDER = /\(domain\)/g;
-const CSP = [
-  "base-uri 'self'",
-  "default-src 'self'",
-  "object-src 'none'",
-  `script-src 'self'${devMode ? " 'unsafe-eval'" : ''}`,
-  `style-src 'self'${
-    devMode
-      ? " 'unsafe-inline'"
-      : " 'sha256-dhQFgDyZCSW+FVxPjFWZQkEnh+5DHADvj1I8rpzmaGU='"
-  }`,
-  'trusted-types dynamic-import',
-  "require-trusted-types-for 'script'",
-  // https://github.com/w3c/webappsec-csp/issues/7 (2023: still required for Mobile Safari)
-  `connect-src 'self' wss://(domain)${devMode ? ' ws://(domain)' : ''}`,
-  "img-src 'self' data: https://*.giphy.com",
-  "form-action 'none'",
-  "frame-ancestors 'none'",
-].join('; ');
-
-const PERMISSIONS_POLICY = [
-  'accelerometer=()',
-  'autoplay=()',
-  'camera=()',
-  'geolocation=()',
-  'gyroscope=()',
-  'interest-cohort=()',
-  'magnetometer=()',
-  'microphone=()',
-  'payment=()',
-  'sync-xhr=()',
-  'usb=()',
-].join(', ');
-
-function getHost(req: { hostname: string }): string {
-  const raw: string = req.hostname;
-  if (raw.includes(':')) {
-    return raw;
-  }
-  // Bug in express 4.x: hostname does not include port
-  // fixed in 5, but not released yet
-  // https://expressjs.com/en/guide/migrating-5.html#req.host
-  return `${raw}:*`;
-}
-
 function readKey(value: string, length: number): Buffer {
   if (!value) {
     return Buffer.alloc(length);
@@ -111,10 +69,7 @@ export const appFactory = async (config: ConfigT): Promise<App> => {
   const userAuthService = new UserAuthService(tokenManager);
   await userAuthService.initialise(db);
 
-  const sso = ab.buildAuthenticationBackend(
-    config.sso,
-    userAuthService.grantLoginToken,
-  );
+  const auth = getAuthBackend(config, userAuthService);
 
   const app = new WebSocketExpress();
 
@@ -126,33 +81,13 @@ export const appFactory = async (config: ConfigT): Promise<App> => {
   app.set('shutdown timeout', 5000);
 
   app.useHTTP((req, res, next) => {
-    res.header('x-frame-options', 'DENY');
-    res.header('x-xss-protection', '1; mode=block');
-    res.header('x-content-type-options', 'nosniff');
-    res.header(
-      'content-security-policy',
-      CSP.replace(CSP_DOMAIN_PLACEHOLDER, getHost(req)),
-    );
-    res.header('permissions-policy', PERMISSIONS_POLICY);
-    res.header('referrer-policy', 'no-referrer');
-    res.header('cross-origin-opener-policy', 'same-origin');
-    // Note: CORP causes manifest icons to fail to load in Chrome Devtools,
-    // but does not break actual functionality
-    // See: https://issues.chromium.org/issues/41451129
-    res.header('cross-origin-resource-policy', 'same-origin');
-    res.header('cross-origin-embedder-policy', 'require-corp');
+    addSecurityHeaders(req, res);
     next();
   });
 
   app.useHTTP('/api', (_, res, next) => {
-    res.header('cache-control', 'no-cache, no-store');
-    res.header('expires', '0');
-    res.header('pragma', 'no-cache');
-    res.removeHeader('content-security-policy');
-    res.removeHeader('permissions-policy');
-    res.removeHeader('referrer-policy');
-    res.removeHeader('cross-origin-opener-policy');
-    res.removeHeader('cross-origin-embedder-policy');
+    removeHtmlSecurityHeaders(res);
+    addNoCacheHeaders(res);
     next();
   });
 
@@ -161,8 +96,8 @@ export const appFactory = async (config: ConfigT): Promise<App> => {
     new ApiAuthRouter(userAuthService, retroAuthService, retroService),
   );
   app.use('/api/slugs', new ApiSlugsRouter(retroService));
-  app.use('/api/config', new ApiConfigRouter(config, sso.service.clientConfig));
-  app.useHTTP('/api/sso', sso.router);
+  app.use('/api/config', new ApiConfigRouter(config, auth.clientConfig));
+  auth.addRoutes(app);
   const apiRetrosRouter = new ApiRetrosRouter(
     userAuthService,
     retroAuthService,
diff --git a/backend/src/config/default.json b/backend/src/config/default.json
index 2a0c6295..9f14ccbb 100644
--- a/backend/src/config/default.json
+++ b/backend/src/config/default.json
@@ -20,6 +20,12 @@
   "db": {
     "url": "memory://refacto"
   },
+  "insecure": {
+    "sharedAccount": {
+      "enabled": false,
+      "authUrl": "/api/open-login"
+    }
+  },
   "sso": {
     "google": {
       "clientId": "",
diff --git a/backend/src/routers/ApiConfigRouter.ts b/backend/src/routers/ApiConfigRouter.ts
index 58d4ed41..e8edcdb5 100644
--- a/backend/src/routers/ApiConfigRouter.ts
+++ b/backend/src/routers/ApiConfigRouter.ts
@@ -1,22 +1,18 @@
 import { Router } from 'websocket-express';
-import { type ClientConfig } from '../shared/api-entities';
-import { type AuthenticationClientConfiguration } from 'authentication-backend';
+import type { ClientConfig } from '../shared/api-entities';
 
 interface ServerConfig {
-  sso: ClientConfig['sso'];
-  giphy: {
-    apiKey: string;
-  };
+  giphy: { apiKey: string };
 }
 
 export class ApiConfigRouter extends Router {
   public constructor(
     serverConfig: ServerConfig,
-    ssoClientConfig: AuthenticationClientConfiguration,
+    ssoClientConfig: ClientConfig['sso'],
   ) {
     super();
 
-    const clientConfig = {
+    const clientConfig: ClientConfig = {
       sso: ssoClientConfig,
       giphy: serverConfig.giphy.apiKey !== '',
     };
diff --git a/docs/SERVICES.md b/docs/SERVICES.md
index 45072a3d..ac95fc32 100644
--- a/docs/SERVICES.md
+++ b/docs/SERVICES.md
@@ -142,6 +142,45 @@ SSO_GITLAB_CLIENT_ID="idhere" \
 ./index.js
 ```
 
+### Public access
+
+If you are running Refacto in a private network where all users are
+trusted, you can set up Refacto to allow all users access to a single
+account. This is simpler than setting up an authentication provider,
+but will allow everybody access to the same account.
+
+```sh
+INSECURE_SHARED_ACCOUNT_ENABLED=true ./index.js
+```
+
+By default this will use `/api/open-login` as the login URL. If you
+want to use a different URL, you can configure it:
+
+```sh
+INSECURE_SHARED_ACCOUNT_ENABLED=true \
+INSECURE_SHARED_ACCOUNT_AUTH_URL="/custom-path" \
+./index.js
+```
+
+You may want to provide some additional security by protecting this
+URL in your proxy. For example, to enable Basic auth using NGINX:
+
+```
+location /api/open-login {
+    auth_basic           "Admin";
+    auth_basic_user_file /etc/apache2/.htpasswd;
+}
+```
+
+Or to enable access only from a specific IP:
+
+```
+location /api/open-login {
+    allow 1.2.3.4/32;
+    deny all;
+}
+```
+
 ## Other Integrations
 
 ### Giphy
diff --git a/frontend/src/components/login/LoginForm.tsx b/frontend/src/components/login/LoginForm.tsx
index 48930c00..72d38db5 100644
--- a/frontend/src/components/login/LoginForm.tsx
+++ b/frontend/src/components/login/LoginForm.tsx
@@ -1,4 +1,4 @@
-import { memo } from 'react';
+import { memo, useLayoutEffect } from 'react';
 import { useConfig } from '../../hooks/data/useConfig';
 import { toHex, randomBytes } from '../../helpers/crypto';
 import { storage } from './storage';
@@ -23,6 +23,8 @@ interface PropsT {
 export const LoginForm = memo(({ message, redirect }: PropsT) => {
   const config = useConfig();
   const sso = config?.sso ?? {};
+
+  const publicConfig = sso['public'];
   const googleConfig = sso['google'];
   const githubConfig = sso['github'];
   const gitlabConfig = sso['gitlab'];
@@ -30,6 +32,16 @@ export const LoginForm = memo(({ message, redirect }: PropsT) => {
   const resolvedRedirect = redirect || document.location.pathname;
   const domain = document.location.origin;
 
+  useLayoutEffect(() => {
+    if (publicConfig) {
+      const targetUrl = new URL('/sso/public', domain);
+      const url = new URL(publicConfig.authUrl, document.location.href);
+      url.searchParams.set('redirect_uri', targetUrl.toString());
+      url.searchParams.set('state', makeState(resolvedRedirect));
+      document.location.href = url.toString();
+    }
+  }, [publicConfig]);
+
   return (
     <div className="login-form">
       {message ? <p>{message}</p> : null}
diff --git a/frontend/src/components/login/handleLogin.ts b/frontend/src/components/login/handleLogin.ts
index 91c708c3..3321d8db 100644
--- a/frontend/src/components/login/handleLogin.ts
+++ b/frontend/src/components/login/handleLogin.ts
@@ -17,7 +17,10 @@ export async function handleLogin(
   const hashParams = new URLSearchParams(hash.substring(1));
   const searchParams = new URLSearchParams(search.substring(1));
 
-  if (service === 'google') {
+  if (service === 'public') {
+    externalToken = hashParams.get('token');
+    state = hashParams.get('state');
+  } else if (service === 'google') {
     externalToken = hashParams.get('id_token');
     state = hashParams.get('state');
   } else if (service === 'github') {