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1---
2alwaysApply: false
3---
4 
5## Use after() for Non-Blocking Operations
6 
7Use Next.js's `after()` to schedule work that should execute after a response is sent. This prevents logging, analytics, and other side effects from blocking the response.
8 
9**Incorrect (blocks response):**
10 
11```tsx
12import { logUserAction } from '@/app/utils'
13 
14export async function POST(request: Request) {
15  // Perform mutation
16  await updateDatabase(request)
17  
18  // Logging blocks the response
19  const userAgent = request.headers.get('user-agent') || 'unknown'
20  await logUserAction({ userAgent })
21  
22  return new Response(JSON.stringify({ status: 'success' }), {
23    status: 200,
24    headers: { 'Content-Type': 'application/json' }
25  })
26}
27```
28 
29**Correct (non-blocking):**
30 
31```tsx
32import { after } from 'next/server'
33import { headers, cookies } from 'next/headers'
34import { logUserAction } from '@/app/utils'
35 
36export async function POST(request: Request) {
37  // Perform mutation
38  await updateDatabase(request)
39  
40  // Log after response is sent
41  after(async () => {
42    const userAgent = (await headers()).get('user-agent') || 'unknown'
43    const sessionCookie = (await cookies()).get('session-id')?.value || 'anonymous'
44    
45    logUserAction({ sessionCookie, userAgent })
46  })
47  
48  return new Response(JSON.stringify({ status: 'success' }), {
49    status: 200,
50    headers: { 'Content-Type': 'application/json' }
51  })
52}
53```
54 
55The response is sent immediately while logging happens in the background.
56 
57**Common use cases:**
58 
59- Analytics tracking
60- Audit logging
61- Sending notifications
62- Cache invalidation
63- Cleanup tasks
64 
65**Important notes:**
66 
67- `after()` runs even if the response fails or redirects
68- Works in Server Actions, Route Handlers, and Server Components
69 
70Reference: [https://nextjs.org/docs/app/api-reference/functions/after](https://nextjs.org/docs/app/api-reference/functions/after)
71