diff --git a/docs/PLAN.md b/docs/PLAN.md
index 04fb45b..396d1c2 100644
--- a/docs/PLAN.md
+++ b/docs/PLAN.md
@@ -21,3 +21,4 @@ Updated: 2026-04-01
 5. Simplified the UI into a calmer minimalist layout with reduced visual noise and denser operational presentation.
 6. Moved user creation into a modal flow and tightened the operator UX with quieter navigation and a denser users table.
 7. Rebuilt the UI shell from scratch around a stable topbar/tab layout with fixed typography and lower visual noise across window sizes.
+8. Corrected the user-creation flow to select a 3proxy service instead of assigning a per-user port, matching the documented 3proxy model.
diff --git a/docs/PROJECT_INDEX.md b/docs/PROJECT_INDEX.md
index 63d1b22..e04ecb7 100644
--- a/docs/PROJECT_INDEX.md
+++ b/docs/PROJECT_INDEX.md
@@ -21,7 +21,7 @@ Updated: 2026-04-01
 - `src/App.tsx`: authenticated panel shell rebuilt around a topbar/tab layout, plus modal user creation flow
 - `src/App.test.tsx`: login-gate and modal interaction tests
 - `src/app.css`: full panel styling
-- `src/data/mockDashboard.ts`: realistic mock state shaped for future API responses
+- `src/data/mockDashboard.ts`: realistic mock state shaped for future API responses, including service-bound users
 - `src/lib/3proxy.ts`: formatting and status helpers
 - `src/lib/3proxy.test.ts`: paranoia-oriented tests for core domain rules
 - `src/test/setup.ts`: Testing Library matchers
diff --git a/src/App.test.tsx b/src/App.test.tsx
index 7102d2e..d868414 100644
--- a/src/App.test.tsx
+++ b/src/App.test.tsx
@@ -1,4 +1,4 @@
-import { render, screen } from '@testing-library/react';
+import { render, screen, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { describe, expect, it } from 'vitest';
 import App from './App';
@@ -40,8 +40,13 @@ describe('App login gate', () => {
     await user.click(screen.getByRole('button', { name: /users/i }));
     await user.click(screen.getByRole('button', { name: /new user/i }));
 
-    expect(screen.getByRole('dialog', { name: /add user/i })).toBeInTheDocument();
+    const dialog = screen.getByRole('dialog', { name: /add user/i });
+
+    expect(dialog).toBeInTheDocument();
     expect(screen.getByPlaceholderText(/night-shift-01/i)).toBeInTheDocument();
+    expect(screen.getByLabelText(/service/i)).toBeInTheDocument();
+    expect(screen.queryByLabelText(/port/i)).not.toBeInTheDocument();
+    expect(within(dialog).getByText(/edge\.example\.net:1080/i)).toBeInTheDocument();
 
     await user.keyboard('{Escape}');
 
diff --git a/src/App.tsx b/src/App.tsx
index 7d53dbd..065d896 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -18,6 +18,14 @@ const tabs: Array<{ id: TabId; label: string }> = [
   { id: 'system', label: 'System' },
 ];
 
+const assignableServices = dashboardSnapshot.system.services.filter(
+  (service) => service.enabled && service.assignable,
+);
+
+const servicesById = new Map(
+  dashboardSnapshot.system.services.map((service) => [service.id, service] as const),
+);
+
 function LoginGate({ onUnlock }: { onUnlock: () => void }) {
   const [login, setLogin] = useState('');
   const [password, setPassword] = useState('');
@@ -71,6 +79,8 @@ function LoginGate({ onUnlock }: { onUnlock: () => void }) {
 }
 
 function AddUserModal({ onClose }: { onClose: () => void }) {
+  const [serviceId, setServiceId] = useState(assignableServices[0]?.id ?? '');
+
   useEffect(() => {
     const handleKeyDown = (event: globalThis.KeyboardEvent) => {
       if (event.key === 'Escape') {
@@ -87,6 +97,8 @@ function AddUserModal({ onClose }: { onClose: () => void }) {
     event.stopPropagation();
   };
 
+  const selectedService = servicesById.get(serviceId);
+
   return (
     <div className="modal-backdrop" role="presentation" onClick={onClose}>
       <section
@@ -112,13 +124,31 @@ function AddUserModal({ onClose }: { onClose: () => void }) {
             <input placeholder="generated secret" />
           </label>
           <label>
-            Port
-            <input placeholder="1080" />
+            Service
+            <select value={serviceId} onChange={(event) => setServiceId(event.target.value)}>
+              {assignableServices.map((service) => (
+                <option key={service.id} value={service.id}>
+                  {service.name}
+                </option>
+              ))}
+            </select>
           </label>
           <label>
             Quota (MB)
             <input placeholder="Optional" />
           </label>
+          <div className="modal-preview">
+            <span>Endpoint</span>
+            <strong>
+              {selectedService
+                ? `${dashboardSnapshot.system.publicHost}:${selectedService.port}`
+                : 'Unavailable'}
+            </strong>
+          </div>
+          <div className="modal-preview">
+            <span>Protocol</span>
+            <strong>{selectedService ? selectedService.protocol : 'Unavailable'}</strong>
+          </div>
           <div className="modal-actions">
             <button type="button" className="button-secondary" onClick={onClose}>
               Cancel
@@ -269,7 +299,19 @@ function UsersTab() {
               </thead>
               <tbody>
                 {dashboardSnapshot.userRecords.map((user) => {
-                  const proxyLink = buildProxyLink(user.username, user.password, user.host, user.port);
+                  const service = servicesById.get(user.serviceId);
+                  const endpoint = service
+                    ? `${dashboardSnapshot.system.publicHost}:${service.port}`
+                    : 'service missing';
+                  const proxyLink = service
+                    ? buildProxyLink(
+                        user.username,
+                        user.password,
+                        dashboardSnapshot.system.publicHost,
+                        service.port,
+                        service.protocol,
+                      )
+                    : '';
                   const exhausted = isQuotaExceeded(user.usedBytes, user.quotaBytes);
 
                   return (
@@ -279,7 +321,12 @@ function UsersTab() {
                           <strong>{user.username}</strong>
                         </div>
                       </td>
-                      <td>{`${user.host}:${user.port}`}</td>
+                      <td>
+                        <div className="endpoint-cell">
+                          <strong>{service?.name ?? 'Unknown service'}</strong>
+                          <span>{endpoint}</span>
+                        </div>
+                      </td>
                       <td>
                         <span className={`status-pill ${getServiceTone(user.status)}`}>{user.status}</span>
                       </td>
@@ -291,6 +338,7 @@ function UsersTab() {
                           type="button"
                           className={exhausted ? 'copy-button danger' : 'copy-button'}
                           onClick={() => handleCopy(user.id, proxyLink)}
+                          disabled={!service}
                         >
                           {copiedId === user.id ? 'Copied' : 'Copy'}
                         </button>
diff --git a/src/app.css b/src/app.css
index 5f4609b..b6dad65 100644
--- a/src/app.css
+++ b/src/app.css
@@ -42,7 +42,8 @@ body {
 }
 
 button,
-input {
+input,
+select {
   font: inherit;
 }
 
@@ -112,7 +113,8 @@ button {
 }
 
 .login-form input,
-.modal-form input {
+.modal-form input,
+.modal-form select {
   width: 100%;
   height: 40px;
   padding: 0 12px;
@@ -123,7 +125,8 @@ button {
 }
 
 .login-form input:focus,
-.modal-form input:focus {
+.modal-form input:focus,
+.modal-form select:focus {
   outline: 2px solid rgba(37, 99, 235, 0.12);
   border-color: var(--accent);
 }
@@ -448,6 +451,15 @@ tbody tr:last-child td {
   font-size: 14px;
 }
 
+.endpoint-cell {
+  display: grid;
+  gap: 2px;
+}
+
+.endpoint-cell span {
+  color: var(--muted);
+}
+
 .status-pill {
   display: inline-flex;
   align-items: center;
@@ -515,6 +527,24 @@ pre {
   grid-template-columns: repeat(2, minmax(0, 1fr));
 }
 
+.modal-preview {
+  display: grid;
+  gap: 4px;
+  padding: 10px 12px;
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  background: var(--surface-muted);
+}
+
+.modal-preview span {
+  color: var(--muted);
+  font-size: 12px;
+}
+
+.modal-preview strong {
+  font-size: 14px;
+}
+
 .modal-actions {
   grid-column: 1 / -1;
   justify-content: flex-end;
diff --git a/src/data/mockDashboard.ts b/src/data/mockDashboard.ts
index 5125d95..1a98adf 100644
--- a/src/data/mockDashboard.ts
+++ b/src/data/mockDashboard.ts
@@ -51,8 +51,7 @@ export const dashboardSnapshot = {
       id: 'u-1',
       username: 'night-shift',
       password: 'kettle!23',
-      host: 'edge.example.net',
-      port: 1080,
+      serviceId: 'socks-main',
       status: 'live' as const,
       usedBytes: 621_805_568,
       quotaBytes: 1_073_741_824,
@@ -61,8 +60,7 @@ export const dashboardSnapshot = {
       id: 'u-2',
       username: 'ops-east',
       password: 'east/line',
-      host: 'edge.example.net',
-      port: 1080,
+      serviceId: 'socks-main',
       status: 'warn' as const,
       usedBytes: 949_010_432,
       quotaBytes: 1_073_741_824,
@@ -71,8 +69,7 @@ export const dashboardSnapshot = {
       id: 'u-3',
       username: 'lab-unlimited',
       password: 'open lane',
-      host: 'edge.example.net',
-      port: 2080,
+      serviceId: 'socks-lab',
       status: 'idle' as const,
       usedBytes: 42_844_160,
       quotaBytes: null,
@@ -81,8 +78,7 @@ export const dashboardSnapshot = {
       id: 'u-4',
       username: 'burst-user',
       password: 'spent-all',
-      host: 'edge.example.net',
-      port: 2080,
+      serviceId: 'socks-lab',
       status: 'fail' as const,
       usedBytes: 1_228_800_000,
       quotaBytes: 1_073_741_824,
@@ -95,22 +91,40 @@ export const dashboardSnapshot = {
     storageMode: 'flat files for config and counters',
     services: [
       {
-        name: 'socks',
+        id: 'socks-main',
+        name: 'SOCKS5 main',
+        protocol: 'socks5',
         description: 'Primary SOCKS5 entrypoint with user auth.',
         port: 1080,
         enabled: true,
+        assignable: true,
       },
       {
-        name: 'admin',
+        id: 'socks-lab',
+        name: 'SOCKS5 lab',
+        protocol: 'socks5',
+        description: 'Secondary SOCKS5 service for lab and overflow users.',
+        port: 2080,
+        enabled: true,
+        assignable: true,
+      },
+      {
+        id: 'admin',
+        name: 'Admin',
+        protocol: 'http',
         description: 'Restricted admin visibility endpoint.',
         port: 8081,
         enabled: true,
+        assignable: false,
       },
       {
-        name: 'proxy',
+        id: 'proxy',
+        name: 'HTTP proxy',
+        protocol: 'http',
         description: 'Optional HTTP/HTTPS proxy profile.',
         port: 3128,
         enabled: false,
+        assignable: true,
       },
     ],
     previewConfig: `daemon