diff --git a/app/admin/auth/page.tsx b/app/admin/auth/page.tsx
index 54006784..1786aba4 100644
--- a/app/admin/auth/page.tsx
+++ b/app/admin/auth/page.tsx
@@ -1,7 +1,7 @@
 'use client';
 
 import { useEffect, useState } from 'react';
-import { Save, Loader2, RotateCcw } from 'lucide-react';
+import { Save, Loader2, RotateCcw, Sparkles } from 'lucide-react';
 import { apiFetch } from '@/lib/browser-navigation';
 
 interface ConfigEntry {
@@ -69,6 +69,47 @@ export default function AdminAuthPage() {
     }
   }
 
+  const [setupRunning, setSetupRunning] = useState(false);
+  const [setupOauthOnly, setSetupOauthOnly] = useState(false);
+
+  async function handleAutoSetup() {
+    if (typeof window === 'undefined') return;
+    const oauthOnlyText = setupOauthOnly ? '\n\n  • Disable password login (OAuth only)' : '';
+    const ok = window.confirm(
+      `Auto-configure OAuth between this webmail and the connected Stalwart server?\n\nThis will:\n  • Create or update an OAuth client called "bulwark-webmail" on the Stalwart server\n  • Generate a new client secret\n  • Register redirect URIs for ${window.location.origin}\n  • Save OAuth settings to admin config (survives env changes)${oauthOnlyText}\n\nYour Stalwart user must have admin permissions.`
+    );
+    if (!ok) return;
+
+    setSetupRunning(true);
+    setMessage(null);
+    try {
+      const res = await apiFetch('/api/admin/oauth/setup', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          origin: window.location.origin,
+          oauthOnly: setupOauthOnly,
+        }),
+      });
+      const data = await res.json();
+      if (res.ok) {
+        setMessage({
+          type: 'success',
+          text: `OAuth client ${data.action} on Stalwart. ${data.redirectUriCount} redirect URI(s) registered. Webmail config updated.`,
+        });
+        setEdits({});
+        await fetchConfig();
+      } else {
+        const detail = data.detail ? ` (${typeof data.detail === 'string' ? data.detail : JSON.stringify(data.detail).slice(0, 200)})` : '';
+        setMessage({ type: 'error', text: (data.error || 'Setup failed') + detail });
+      }
+    } catch (err) {
+      setMessage({ type: 'error', text: err instanceof Error ? err.message : 'Setup failed' });
+    } finally {
+      setSetupRunning(false);
+    }
+  }
+
   const hasEdits = Object.keys(edits).length > 0;
 
   if (loading) {
@@ -100,6 +141,40 @@ export default function AdminAuthPage() {
         </div>
       )}
 
+      {/* Auto-setup */}
+      <div className="rounded-lg border border-primary/30 bg-primary/5 p-4">
+        <div className="flex items-start justify-between gap-4">
+          <div className="min-w-0">
+            <div className="flex items-center gap-2">
+              <Sparkles className="w-4 h-4 text-primary shrink-0" />
+              <h3 className="text-sm font-medium text-foreground">Auto-configure OAuth (Stalwart)</h3>
+            </div>
+            <p className="text-xs text-muted-foreground mt-1">
+              Registers an OAuth client on the connected Stalwart server, generates a client secret, and saves the settings here.
+              Requires your Stalwart account to have admin permissions.
+            </p>
+            <label className="inline-flex items-center gap-2 mt-3 text-xs text-foreground select-none cursor-pointer">
+              <input
+                type="checkbox"
+                checked={setupOauthOnly}
+                onChange={(e) => setSetupOauthOnly(e.target.checked)}
+                className="h-3.5 w-3.5 rounded border-input"
+                disabled={setupRunning}
+              />
+              Also enable “OAuth only” (hide password login)
+            </label>
+          </div>
+          <button
+            onClick={handleAutoSetup}
+            disabled={setupRunning}
+            className="shrink-0 inline-flex items-center gap-2 h-9 px-4 rounded-md bg-primary text-primary-foreground text-sm font-medium hover:bg-primary/90 disabled:opacity-50 transition-all shadow-sm"
+          >
+            {setupRunning ? <Loader2 className="w-4 h-4 animate-spin" /> : <Sparkles className="w-4 h-4" />}
+            {setupRunning ? 'Configuring…' : 'Set up automagically'}
+          </button>
+        </div>
+      </div>
+
       {/* OAuth */}
       <Section title="OAuth / OpenID Connect">
         <Toggle label="OAuth Enabled" configKey="oauthEnabled" value={currentValue('oauthEnabled') as boolean} source={config.oauthEnabled?.source} onChange={handleChange} onRevert={handleRevert} />
diff --git a/app/api/admin/oauth/setup/route.ts b/app/api/admin/oauth/setup/route.ts
new file mode 100644
index 00000000..b4cde06a
--- /dev/null
+++ b/app/api/admin/oauth/setup/route.ts
@@ -0,0 +1,238 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { randomBytes } from 'node:crypto';
+import { requireAdminAuth, getClientIP } from '@/lib/admin/session';
+import { getStalwartCredentials } from '@/lib/stalwart/credentials';
+import { configManager } from '@/lib/admin/config-manager';
+import { auditLog } from '@/lib/admin/audit';
+import { logger } from '@/lib/logger';
+import { locales as ALL_LOCALES } from '@/i18n/routing';
+
+const CLIENT_ID = 'bulwark-webmail';
+const CLIENT_DESCRIPTION = 'Bulwark Webmail (auto-configured)';
+const JMAP_TIMEOUT_MS = 10_000;
+
+interface JmapMethodCall {
+  using: string[];
+  methodCalls: Array<[string, Record<string, unknown>, string]>;
+}
+
+interface JmapMethodResponse {
+  methodResponses?: Array<[string, Record<string, unknown>, string]>;
+}
+
+async function fetchWithTimeout(url: string, init: Parameters<typeof fetch>[1]): Promise<Response> {
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), JMAP_TIMEOUT_MS);
+  try {
+    return await fetch(url, { ...init, signal: controller.signal });
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
+async function jmapCall(
+  serverUrl: string,
+  authHeader: string,
+  body: JmapMethodCall,
+): Promise<JmapMethodResponse> {
+  const res = await fetchWithTimeout(`${serverUrl}/jmap/`, {
+    method: 'POST',
+    headers: { 'Authorization': authHeader, 'Content-Type': 'application/json' },
+    body: JSON.stringify(body),
+  });
+  if (!res.ok) {
+    const text = await res.text().catch(() => '');
+    throw new Error(`JMAP HTTP ${res.status} ${text.slice(0, 200)}`);
+  }
+  return res.json() as Promise<JmapMethodResponse>;
+}
+
+async function getStalwartAccountId(
+  serverUrl: string,
+  authHeader: string,
+): Promise<string | null> {
+  const res = await fetchWithTimeout(`${serverUrl}/.well-known/jmap`, {
+    method: 'GET',
+    headers: { 'Authorization': authHeader },
+  });
+  if (!res.ok) return null;
+  const session = await res.json() as { primaryAccounts?: Record<string, string> };
+  return session.primaryAccounts?.['urn:stalwart:jmap']
+    ?? session.primaryAccounts?.['urn:ietf:params:jmap:mail']
+    ?? Object.values(session.primaryAccounts ?? {})[0]
+    ?? null;
+}
+
+function buildRedirectUris(origin: string, localeList: readonly string[]): Record<string, true> {
+  const out: Record<string, true> = {};
+  for (const loc of localeList) {
+    out[`${origin}/${loc}/auth/callback`] = true;
+  }
+  return out;
+}
+
+interface SetupRequestBody {
+  origin?: string;
+  locales?: string[];
+  oauthOnly?: boolean;
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const auth = await requireAdminAuth();
+    if ('error' in auth) return auth.error;
+
+    const ip = getClientIP(request);
+    const creds = await getStalwartCredentials(request);
+    if (!creds) {
+      return NextResponse.json(
+        { error: 'No Stalwart session available. Sign in to your mail account in another tab and retry.' },
+        { status: 400 },
+      );
+    }
+
+    const body = await request.json() as SetupRequestBody;
+    const origin = (body.origin ?? '').trim().replace(/\/+$/, '');
+    if (!/^https?:\/\/[^/]+$/.test(origin)) {
+      return NextResponse.json(
+        { error: 'Origin must be a URL like "https://mail.example.com" with no path.' },
+        { status: 400 },
+      );
+    }
+    const localeList = Array.isArray(body.locales) && body.locales.length > 0
+      ? body.locales.filter(l => typeof l === 'string' && /^[a-z]{2,5}(-[A-Za-z0-9]+)*$/.test(l))
+      : Array.from(ALL_LOCALES);
+    if (localeList.length === 0) {
+      return NextResponse.json({ error: 'No valid locales supplied.' }, { status: 400 });
+    }
+    const oauthOnly = body.oauthOnly === true;
+
+    const accountId = await getStalwartAccountId(creds.serverUrl, creds.authHeader);
+    if (!accountId) {
+      return NextResponse.json(
+        { error: 'Could not resolve Stalwart account from JMAP session.' },
+        { status: 502 },
+      );
+    }
+
+    const queryRes = await jmapCall(creds.serverUrl, creds.authHeader, {
+      using: ['urn:ietf:params:jmap:core', 'urn:stalwart:jmap'],
+      methodCalls: [[
+        'x:OAuthClient/query',
+        { accountId, filter: { clientId: CLIENT_ID } },
+        '0',
+      ]],
+    });
+
+    const queryEntry = queryRes.methodResponses?.[0];
+    if (!queryEntry || queryEntry[0] === 'error') {
+      return NextResponse.json({
+        error: 'Stalwart denied OAuthClient/query — your Stalwart account likely lacks admin permissions.',
+        detail: queryEntry?.[1],
+      }, { status: 403 });
+    }
+    const existingIds = (queryEntry[1].ids as string[] | undefined) ?? [];
+
+    const secret = randomBytes(32).toString('base64url');
+    const redirectUris = buildRedirectUris(origin, localeList);
+
+    let setArgs: Record<string, unknown>;
+    let action: 'created' | 'updated';
+    if (existingIds.length > 0) {
+      const targetId = existingIds[0];
+      action = 'updated';
+      setArgs = {
+        accountId,
+        update: {
+          [targetId]: {
+            secret,
+            redirectUris,
+            description: CLIENT_DESCRIPTION,
+          },
+        },
+      };
+    } else {
+      action = 'created';
+      setArgs = {
+        accountId,
+        create: {
+          new: {
+            clientId: CLIENT_ID,
+            description: CLIENT_DESCRIPTION,
+            secret,
+            redirectUris,
+            contacts: { [creds.username]: true },
+          },
+        },
+      };
+    }
+
+    const setRes = await jmapCall(creds.serverUrl, creds.authHeader, {
+      using: ['urn:ietf:params:jmap:core', 'urn:stalwart:jmap'],
+      methodCalls: [['x:OAuthClient/set', setArgs, '0']],
+    });
+
+    const setEntry = setRes.methodResponses?.[0];
+    if (!setEntry || setEntry[0] === 'error') {
+      return NextResponse.json({
+        error: 'Stalwart denied OAuthClient/set — admin permissions required.',
+        detail: setEntry?.[1],
+      }, { status: 403 });
+    }
+    const setBody = setEntry[1] as {
+      notCreated?: Record<string, unknown>;
+      notUpdated?: Record<string, unknown>;
+    };
+    if (setBody.notCreated && Object.keys(setBody.notCreated).length > 0) {
+      return NextResponse.json(
+        { error: 'Stalwart refused to create the OAuth client.', detail: setBody.notCreated },
+        { status: 502 },
+      );
+    }
+    if (setBody.notUpdated && Object.keys(setBody.notUpdated).length > 0) {
+      return NextResponse.json(
+        { error: 'Stalwart refused to update the OAuth client.', detail: setBody.notUpdated },
+        { status: 502 },
+      );
+    }
+
+    await configManager.ensureLoaded();
+    const updates: Record<string, unknown> = {
+      oauthEnabled: true,
+      oauthClientId: CLIENT_ID,
+      oauthClientSecret: secret,
+      oauthIssuerUrl: origin,
+    };
+    if (oauthOnly) updates.oauthOnly = true;
+    await configManager.setAdminConfig(updates);
+
+    await auditLog('admin.oauth_setup', {
+      action,
+      clientId: CLIENT_ID,
+      issuer: origin,
+      redirectUriCount: localeList.length,
+      oauthOnly,
+    }, ip);
+
+    logger.info('Admin OAuth setup', {
+      action,
+      clientId: CLIENT_ID,
+      issuer: origin,
+      locales: localeList.length,
+    });
+
+    return NextResponse.json({
+      ok: true,
+      action,
+      clientId: CLIENT_ID,
+      issuerUrl: origin,
+      redirectUriCount: localeList.length,
+    });
+  } catch (error) {
+    logger.error('Admin OAuth setup error', { error: error instanceof Error ? error.message : 'Unknown error' });
+    return NextResponse.json(
+      { error: error instanceof Error ? error.message : 'Internal server error' },
+      { status: 500 },
+    );
+  }
+}
diff --git a/app/api/auth/session/route.ts b/app/api/auth/session/route.ts
index 06d11230..e9f9a7cf 100644
--- a/app/api/auth/session/route.ts
+++ b/app/api/auth/session/route.ts
@@ -9,6 +9,7 @@ import {
   clearStalwartAuthContextInStore,
   setStalwartAuthContextInStore,
 } from '@/lib/stalwart/auth-context';
+import { configManager } from '@/lib/admin/config-manager';
 
 const COOKIE_OPTIONS = {
   ...getCookieOptions(),
@@ -25,7 +26,9 @@ function getSlot(request: NextRequest): number {
 
 export async function POST(request: NextRequest) {
   try {
-    if (process.env.OAUTH_ENABLED === 'true' && process.env.OAUTH_ONLY === 'true') {
+    const oauthEnabled = configManager.get<boolean>('oauthEnabled', false);
+    const oauthOnly = configManager.get<boolean>('oauthOnly', false);
+    if (oauthEnabled && oauthOnly) {
       return NextResponse.json({ error: 'Basic authentication is disabled' }, { status: 403 });
     }
 
diff --git a/app/api/auth/totp-token-exchange/route.ts b/app/api/auth/totp-token-exchange/route.ts
index 39ef5bac..2ee7226b 100644
--- a/app/api/auth/totp-token-exchange/route.ts
+++ b/app/api/auth/totp-token-exchange/route.ts
@@ -5,6 +5,7 @@ import { discoverOAuth } from '@/lib/oauth/discovery';
 import { refreshTokenCookieName } from '@/lib/oauth/tokens';
 import { getCookieOptions } from '@/lib/oauth/cookie-config';
 import { readFileEnv } from '@/lib/read-file-env';
+import { configManager } from '@/lib/admin/config-manager';
 
 /**
  * Exchange basic auth credentials (with TOTP appended) for OAuth tokens.
@@ -113,8 +114,8 @@ async function attemptAllStrategies(
 ): Promise<NextResponse> {
   logger.info('TOTP token exchange: found token endpoint', { tokenEndpoint });
 
-  const clientId = process.env.OAUTH_CLIENT_ID;
-  const clientSecret = process.env.OAUTH_CLIENT_SECRET || readFileEnv(process.env.OAUTH_CLIENT_SECRET_FILE);
+  const clientId = configManager.get<string>('oauthClientId', '') || process.env.OAUTH_CLIENT_ID;
+  const clientSecret = configManager.get<string>('oauthClientSecret', '') || process.env.OAUTH_CLIENT_SECRET || readFileEnv(process.env.OAUTH_CLIENT_SECRET_FILE);
   const basicAuth = `Basic ${Buffer.from(`${username}:${password}`).toString('base64')}`;
   const attempts: Array<{ strategy: string; error: string }> = [];
 
diff --git a/lib/oauth/token-exchange.ts b/lib/oauth/token-exchange.ts
index abeb2348..c54a92ed 100644
--- a/lib/oauth/token-exchange.ts
+++ b/lib/oauth/token-exchange.ts
@@ -2,18 +2,23 @@ import { logger } from '@/lib/logger';
 import { discoverOAuth } from '@/lib/oauth/discovery';
 import type { OAuthMetadata } from '@/lib/oauth/discovery';
 import { readFileEnv } from '@/lib/read-file-env';
+import { configManager } from '@/lib/admin/config-manager';
 
-const CLIENT_SECRET = process.env.OAUTH_CLIENT_SECRET || readFileEnv(process.env.OAUTH_CLIENT_SECRET_FILE) || '';
+function getClientSecret(): string {
+  const adminSecret = configManager.get<string>('oauthClientSecret', '');
+  if (adminSecret) return adminSecret;
+  return process.env.OAUTH_CLIENT_SECRET || readFileEnv(process.env.OAUTH_CLIENT_SECRET_FILE) || '';
+}
 
 export function getRequiredConfig() {
-  const clientId = process.env.OAUTH_CLIENT_ID;
-  const serverUrl = process.env.JMAP_SERVER_URL || process.env.NEXT_PUBLIC_JMAP_SERVER_URL;
-  const issuerUrl = process.env.OAUTH_ISSUER_URL;
+  const clientId = configManager.get<string>('oauthClientId', '') || process.env.OAUTH_CLIENT_ID;
+  const serverUrl = configManager.get<string>('jmapServerUrl', '') || process.env.JMAP_SERVER_URL || process.env.NEXT_PUBLIC_JMAP_SERVER_URL;
+  const issuerUrl = configManager.get<string>('oauthIssuerUrl', '') || process.env.OAUTH_ISSUER_URL;
   if (!clientId || !serverUrl) {
     throw new Error(`OAuth misconfigured: ${[!clientId && 'OAUTH_CLIENT_ID', !serverUrl && 'JMAP_SERVER_URL'].filter(Boolean).join(', ')} not set`);
   }
   const discoveryUrl = issuerUrl?.trim() || serverUrl;
-  if (issuerUrl !== undefined && !issuerUrl.trim()) {
+  if (issuerUrl !== undefined && issuerUrl !== '' && !issuerUrl.trim()) {
     logger.warn('OAUTH_ISSUER_URL is set but empty, falling back to JMAP_SERVER_URL for discovery');
   }
   return { clientId, serverUrl, discoveryUrl };
@@ -36,8 +41,9 @@ export async function getMetadata(): Promise<OAuthMetadata | null> {
 export function buildOAuthParams(base: Record<string, string>): URLSearchParams {
   const { clientId } = getRequiredConfig();
   const params = new URLSearchParams({ ...base, client_id: clientId });
-  if (CLIENT_SECRET) {
-    params.set('client_secret', CLIENT_SECRET);
+  const secret = getClientSecret();
+  if (secret) {
+    params.set('client_secret', secret);
   }
   return params;
 }