Subchapter 152.4
references/link-session-replay.mdMarkdown5 KBView on GitHub
Connecting your backend logs to frontend session replays provides complete visibility into the user journey, helping you understand the full context around issues in your application.
By including session IDs and user identity in your logs, you can:
posthogDistinctId without session replay to link logs to a user profile)To link logs to session replays, you need to pass the session ID and user identity from your frontend to your backend, then include them as log attributes.
In your frontend code, retrieve the current session ID and send it with your API requests:
JavaScript
PostHog AI
// In your frontend code
import posthog from 'posthog-js'
// Get the current session ID
const sessionId = posthog.getSessionId()
// Send it with your API request
const response = await fetch('/api/chat', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({
message: userInput,
sessionId: sessionId // Include session ID
})
})Once you have the session ID, include it along with the user’s identity using the sessionId and posthogDistinctId attributes. These examples assume you’ve already set up a logging client (opens in a new tab) for your language.
PostHog AI
import { logs } from '@opentelemetry/api-logs'
const logger = logs.getLogger('my-app')
app.post('/api/chat', async (req, res) => {
const { message, sessionId } = req.body
const userId = req.userId // ... get your user ID
logger.emit({
severityText: 'info',
body: 'Chat request received',
attributes: {
posthogDistinctId: userId, // Links to PostHog user
sessionId: sessionId, // Links to session replay
endpoint: '/api/chat',
},
})
// ... handle the request
res.json({ success: true })
})import logging
logger = logging.getLogger(__name__)
@app.route('/api/chat', methods=['POST'])
def chat():
data = request.json
message = data['message']
session_id = data.get('sessionId')
user_id = current_user.id
logger.info(
"Chat request received",
extra={
"posthogDistinctId": user_id, # Links to PostHog user
"sessionId": session_id, # Links to session replay
"endpoint": "/api/chat",
}
)
# ... handle the request
return jsonify({"success": True})Note: If you don’t include
posthogDistinctId, logs won’t be linked to a user. If you don’t includesessionId, logs won’t be linked to a session replay. You can use either or both independently.
Once you’ve set up session linking, you can navigate from logs to their corresponding session replays:
You can only view recordings for log entries that have an associated session ID.
This linking helps you correlate backend log events with actual frontend user behavior, enabling faster debugging and better understanding of issues as they occur in your application.
When you click on a log entry that has a session ID, you can view related errors in the Related errors tab. This tab shows Error Tracking issues that occurred within the same session (within ±6 hours of the log timestamp).
This helps you debug issues by showing errors that happened around the same time as your log entry, giving you a more complete picture of what went wrong.
If no session ID is found in the log entry, the tab displays a message prompting you to link your logs to sessions.
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