docs: add groups

apps/public/content/docs/(tracking)/sdks/express.mdx

@@ -68,6 +68,34 @@ app.listen(3000, () => {
 - `trackRequest` - A function that returns `true` if the request should be tracked.
 - `getProfileId` - A function that returns the profile ID of the user making the request.
 
+## Working with Groups
+
+Groups let you track analytics at the account or company level. Since Express is a backend SDK, you can upsert groups and assign users from your route handlers.
+
+See the [Groups guide](/docs/get-started/groups) for the full walkthrough.
+
+```ts
+app.post('/login', async (req, res) => {
+  const user = await loginUser(req.body);
+
+  // Identify the user
+  req.op.identify({ profileId: user.id, email: user.email });
+
+  // Create/update the group entity
+  req.op.upsertGroup({
+    id: user.organizationId,
+    type: 'company',
+    name: user.organizationName,
+    properties: { plan: user.plan },
+  });
+
+  // Assign the user to the group
+  req.op.setGroup(user.organizationId);
+
+  res.json({ ok: true });
+});
+```
+
 ## Typescript
 
 If `req.op` is not typed you can extend the `Request` interface.

apps/public/content/docs/(tracking)/sdks/javascript.mdx

@@ -116,9 +116,38 @@ op.decrement({
 });
 ```
 
+### Working with Groups
+
+Groups let you track analytics at the account or company level. See the [Groups guide](/docs/get-started/groups) for the full walkthrough.
+
+**Create or update a group:**
+
+```js title="index.js"
+import { op } from './op.ts'
+
+op.upsertGroup({
+  id: 'org_acme',
+  type: 'company',
+  name: 'Acme Inc',
+  properties: { plan: 'enterprise' },
+});
+```
+
+**Assign the current user to a group** (call after `identify`):
+
+```js title="index.js"
+import { op } from './op.ts'
+
+op.setGroup('org_acme');
+// or multiple groups:
+op.setGroups(['org_acme', 'team_eng']);
+```
+
+Once set, all subsequent `track()` calls will automatically include the group IDs.
+
 ### Clearing User Data
 
-To clear the current user's data:
+To clear the current user's data (including groups):
 
 ```js title="index.js"
 import { op } from './op.ts'

apps/public/content/docs/(tracking)/sdks/nextjs.mdx

@@ -227,9 +227,32 @@ useOpenPanel().decrement({
 });
 ```
 
+### Working with Groups
+
+Groups let you track analytics at the account or company level. See the [Groups guide](/docs/get-started/groups) for the full walkthrough.
+
+**Create or update a group:**
+
+```tsx title="app/login/page.tsx"
+useOpenPanel().upsertGroup({
+  id: 'org_acme',
+  type: 'company',
+  name: 'Acme Inc',
+  properties: { plan: 'enterprise' },
+});
+```
+
+**Assign the current user to a group** (call after `identify`):
+
+```tsx title="app/login/page.tsx"
+useOpenPanel().setGroup('org_acme');
+```
+
+Once set, all subsequent `track()` calls will automatically include the group IDs.
+
 ### Clearing User Data
 
-To clear the current user's data:
+To clear the current user's data (including groups):
 
 ```js title="index.js"
 useOpenPanel().clear()

apps/public/content/docs/(tracking)/sdks/react.mdx

@@ -174,9 +174,37 @@ function MyComponent() {
 }
 ```
 
+### Working with Groups
+
+Groups let you track analytics at the account or company level. See the [Groups guide](/docs/get-started/groups) for the full walkthrough.
+
+```tsx
+import { op } from '@/openpanel';
+
+function LoginComponent() {
+  const handleLogin = async (user: User) => {
+    // 1. Identify the user
+    op.identify({ profileId: user.id, email: user.email });
+
+    // 2. Create/update the group entity (only when data changes)
+    op.upsertGroup({
+      id: user.organizationId,
+      type: 'company',
+      name: user.organizationName,
+      properties: { plan: user.plan },
+    });
+
+    // 3. Link the user to their group — tags all future events
+    op.setGroup(user.organizationId);
+  };
+
+  return <button onClick={() => handleLogin(user)}>Login</button>;
+}
+```
+
 ### Clearing User Data
 
-To clear the current user's data:
+To clear the current user's data (including groups):
 
 ```tsx
 import { op } from '@/openpanel';