Add guide for tracking customer transcription usage (async + streaming)

fern/docs.yml

@@ -820,6 +820,13 @@ navigation:
                   - link: Speechmatics to AssemblyAI
                     href: /docs/guides/speechmatics_to_aai_streaming
 
+          - section: Platform
+            skip-slug: true
+            contents:
+              - page: Tracking customer transcription usage
+                path: pages/05-guides/billing-tracking.mdx
+                slug: tracking-your-customers-usage
+
           # Legacy guides
           - page: Process Speaker Labels with LeMURs Custom Text Input Parameter
             path: pages/05-guides/cookbooks/lemur/input-text-speaker-labels.mdx

fern/pages/05-guides/billing-tracking.mdx

@@ -0,0 +1,345 @@
+---
+title: "Tracking customer transcription usage"
+hide-nav-links: true
+description: "Learn how to track individual customer usage within your product using AssemblyAI's webhook system and metadata."
+---
+
+This guide explains how to track individual customer usage within your product for billing purposes.
+
+<Note>
+This is the recommended approach for tracking customer usage. Creating separate API keys for each of your customers is not an optimal strategy for usage tracking, as it adds unnecessary complexity and makes it harder to manage your account.
+</Note>
+
+There are two separate methods depending on which transcription approach you use:
+
+1. **Async transcription**: Use webhooks with custom query parameters to associate transcriptions with customers, then retrieve the `audio_duration` from the transcript response.
+
+2. **Streaming transcription**: Manage customer IDs in your application state and capture the `session_duration_seconds` from the WebSocket Termination event.
+
+This guide covers both methods in detail.
+
+## Async transcription usage tracking
+
+By combining webhooks with custom metadata, you can track audio duration per customer and monitor their usage of your transcription service.
+
+### Step 1: Set up webhooks with customer metadata
+
+When submitting a transcription request, include your webhook URL with the customer ID as a query parameter. This allows you to associate each transcription with a specific customer.
+
+<Tabs>
+<Tab language="python-sdk" title="Python SDK">
+
+```python
+import assemblyai as aai
+
+aai.settings.api_key = "<YOUR_API_KEY>"
+
+# Add customer_id as a query parameter to your webhook URL
+webhook_url = "https://your-domain.com/webhook?customer_id=customer_123"
+
+config = aai.TranscriptionConfig(
+    speech_model=aai.SpeechModel.best
+).set_webhook(webhook_url)
+
+# Submit without waiting for completion
+aai.Transcriber().submit("https://example.com/audio.mp3", config)
+```
+
+</Tab>
+<Tab language="python" title="Python">
+
+```python
+import requests
+
+base_url = "https://api.assemblyai.com"
+headers = {"authorization": "<YOUR_API_KEY>"}
+
+# Add customer_id as a query parameter to your webhook URL
+webhook_url = "https://your-domain.com/webhook?customer_id=customer_123"
+
+data = {
+    "audio_url": "https://example.com/audio.mp3",
+    "webhook_url": webhook_url
+}
+
+# Submit without waiting for completion
+response = requests.post(base_url + "/v2/transcript", headers=headers, json=data)
+transcript_id = response.json()["id"]
+```
+
+</Tab>
+<Tab language="javascript-sdk" title="JavaScript SDK">
+
+```javascript
+import { AssemblyAI } from "assemblyai";
+
+const client = new AssemblyAI({
+  apiKey: "<YOUR_API_KEY>",
+});
+
+// Add customer_id as a query parameter to your webhook URL
+const webhookUrl = "https://your-domain.com/webhook?customer_id=customer_123";
+
+const transcript = await client.transcripts.submit({
+  audio: "https://example.com/audio.mp3",
+  speech_model: "best",
+  webhook_url: webhookUrl,
+});
+```
+
+</Tab>
+<Tab language="javascript" title="JavaScript">
+
+```javascript
+import axios from "axios";
+
+const baseUrl = "https://api.assemblyai.com";
+const headers = { authorization: "<YOUR_API_KEY>" };
+
+// Add customer_id as a query parameter to your webhook URL
+const webhookUrl = "https://your-domain.com/webhook?customer_id=customer_123";
+
+const data = {
+  audio_url: "https://example.com/audio.mp3",
+  webhook_url: webhookUrl,
+};
+
+// Submit without waiting for completion
+const response = await axios.post(`${baseUrl}/v2/transcript`, data, { headers });
+const transcriptId = response.data.id;
+```
+
+</Tab>
+</Tabs>
+
+You can add multiple query parameters to track additional information:
+
+```
+https://your-domain.com/webhook?customer_id=123&project_id=456&order_id=789
+```
+
+This allows you to track usage across multiple dimensions (customer, project, order, etc.).
+
+### Step 2: Handle the webhook delivery
+
+When the transcription completes, AssemblyAI sends a POST request to your webhook URL with the following payload:
+
+```json
+{
+  "transcript_id": "5552493-16d8-42d8-8feb-c2a16b56f6e8",
+  "status": "completed"
+}
+```
+
+Extract both the `transcript_id` from the payload and the `customer_id` from your URL query parameters.
+
+### Step 3: Retrieve the transcript with audio duration
+
+Use the transcript ID to fetch the complete transcript details, which includes the `audio_duration` field (in seconds).
+
+<Tabs>
+<Tab language="python-sdk" title="Python SDK">
+
+```python
+import assemblyai as aai
+
+aai.settings.api_key = "<YOUR_API_KEY>"
+
+# Get transcript using the ID from webhook
+transcript = aai.Transcript.get_by_id("<TRANSCRIPT_ID>")
+
+if transcript.status == aai.TranscriptStatus.completed:
+    audio_duration = transcript.audio_duration  # Duration in seconds
+    # Use audio_duration for billing/tracking
+```
+
+</Tab>
+<Tab language="python" title="Python">
+
+```python
+import requests
+
+base_url = "https://api.assemblyai.com"
+headers = {"authorization": "<YOUR_API_KEY>"}
+
+# Get transcript using the ID from webhook
+response = requests.get(base_url + "/v2/transcript/<TRANSCRIPT_ID>", headers=headers)
+transcript = response.json()
+
+if transcript["status"] == "completed":
+    audio_duration = transcript["audio_duration"]  # Duration in seconds
+    # Use audio_duration for billing/tracking
+```
+
+</Tab>
+<Tab language="javascript-sdk" title="JavaScript SDK">
+
+```javascript
+import { AssemblyAI } from "assemblyai";
+
+const client = new AssemblyAI({
+  apiKey: "<YOUR_API_KEY>",
+});
+
+// Get transcript using the ID from webhook
+const transcript = await client.transcripts.get("<TRANSCRIPT_ID>");
+
+if (transcript.status === "completed") {
+  const audioDuration = transcript.audio_duration; // Duration in seconds
+  // Use audioDuration for billing/tracking
+}
+```
+
+</Tab>
+<Tab language="javascript" title="JavaScript">
+
+```javascript
+import axios from "axios";
+
+const baseUrl = "https://api.assemblyai.com";
+const headers = { authorization: "<YOUR_API_KEY>" };
+
+// Get transcript using the ID from webhook
+const response = await axios.get(`${baseUrl}/v2/transcript/<TRANSCRIPT_ID>`, { headers });
+const transcript = response.data;
+
+if (transcript.status === "completed") {
+  const audioDuration = transcript.audio_duration; // Duration in seconds
+  // Use audioDuration for billing/tracking
+}
+```
+
+</Tab>
+</Tabs>
+
+### Step 4: Track usage per customer
+
+In your webhook handler, combine the customer ID from your webhook URL query parameters with the audio duration from the transcript to record usage:
+
+1. Extract the `customer_id` from the webhook URL query parameters
+2. Extract the `transcript_id` from the webhook payload
+3. If the status is `completed`, fetch the transcript using the SDK to get the `audio_duration`
+4. Store the usage record in your database with the customer ID, transcript ID, audio duration, and timestamp
+
+This allows you to aggregate usage per customer for billing purposes.
+
+## Streaming transcription usage tracking
+
+Unlike async transcription which uses webhooks, streaming transcription requires a different approach. You'll track usage by managing customer IDs in your own application state/session management, capturing the `session_duration_seconds` from the Termination event, and associating the duration with the customer ID for billing/tracking. AssemblyAI bills streaming based on session duration, so this is the metric you should track.
+
+### Step 1: Set up your WebSocket connection
+
+Connect to AssemblyAI's streaming service. The customer ID is managed entirely in your application and is never sent to AssemblyAI.
+
+```python
+import websocket
+import json
+from urllib.parse import urlencode
+from datetime import datetime
+
+# Configuration
+YOUR_API_KEY = "<YOUR_API_KEY>"
+
+CONNECTION_PARAMS = {
+    "sample_rate": 16000,
+    "format_turns": True,
+}
+
+API_ENDPOINT = f"wss://streaming.assemblyai.com/v3/ws?{urlencode(CONNECTION_PARAMS)}"
+```
+
+### Step 2: Capture audio duration from the Termination event
+
+The key to tracking usage is capturing the `audio_duration_seconds` field from the Termination message. This is sent when the streaming session ends.
+
+```python
+def on_message(ws, message):
+    """Handle WebSocket messages"""
+    try:
+        data = json.loads(message)
+        msg_type = data.get("type")
+
+        if msg_type == "Begin":
+            session_id = data.get("id")
+            print(f"Session started: {session_id}")
+
+        elif msg_type == "Turn":
+            transcript = data.get("transcript", "")
+            if data.get("turn_is_formatted"):
+                print(f"Transcript: {transcript}")
+
+        elif msg_type == "Termination":
+            # Extract audio duration - this is what you need for billing
+            audio_duration_seconds = data.get("audio_duration_seconds", 0)
+            session_duration_seconds = data.get("session_duration_seconds", 0)
+
+            print(f"\nSession terminated:")
+            print(f"  Audio Duration: {audio_duration_seconds} seconds")
+            print(f"  Session Duration: {session_duration_seconds} seconds")
+
+            # Here you would associate audio_duration_seconds with your customer
+            # using whatever session management system you have in place
+            customer_id = get_customer_id_from_session()  # Your implementation
+            log_customer_usage(customer_id, session_duration_seconds)
+
+    except json.JSONDecodeError as e:
+        print(f"Error decoding message: {e}")
+    except Exception as e:
+        print(f"Error handling message: {e}")
+```
+
+### Step 3: Log customer usage
+
+When you receive the Termination event, store the session duration for billing/tracking:
+
+1. Retrieve the customer ID from your session management system (authentication tokens, session cookies, etc.)
+2. Extract the `session_duration_seconds` from the Termination event
+3. Store the usage record in your database with the customer ID, session duration, and timestamp
+
+Since AssemblyAI bills streaming based on `session_duration_seconds`, this is the metric you should track for accurate billing.
+
+### Session duration vs audio duration
+
+From the Termination event, you receive two fields:
+
+| Field | Description |
+|-------|-------------|
+| `session_duration_seconds` | Total time the session was open |
+| `audio_duration_seconds` | Total seconds of audio actually processed |
+
+<Note>
+Streaming transcription is billed based on `session_duration_seconds`, not `audio_duration_seconds`. Make sure you track the correct metric for accurate billing.
+</Note>
+
+### Session management
+
+You need to implement your own session management to associate WebSocket connections with customer IDs. This could be through user authentication tokens, session cookies, database lookups, or in-memory session stores. Track the customer ID throughout the WebSocket lifecycle so you can associate it with the session duration when the Termination event arrives.
+
+### Proper session termination
+
+Always close sessions properly to ensure you receive the Termination event and avoid unexpected costs:
+
+```python
+# Send termination message when done
+terminate_message = {"type": "Terminate"}
+ws.send(json.dumps(terminate_message))
+```
+
+## Best practices
+
+When implementing billing tracking, consider the following best practices:
+
+1. **Store the transcript/session ID**: Always store the identifier alongside usage records. This allows you to audit and verify billing data.
+
+2. **Handle errors gracefully**: If a transcription fails (`status: "error"`), don't bill the customer for that request. You may want to log failed transcriptions for debugging.
+
+3. **Secure your webhooks**: Use the `webhook_auth_header_name` and `webhook_auth_header_value` parameters to verify that webhook requests are from AssemblyAI.
+
+4. **Consider time zones**: Store timestamps in UTC to avoid confusion when generating billing reports.
+
+## Next steps
+
+- Learn more about [webhooks](/docs/deployment/webhooks) and their configuration options
+- Explore the [Submit Transcript API](/docs/api-reference/transcripts/submit) for async transcription
+- Explore the [Get Transcript API](/docs/api-reference/transcripts/get) for retrieving transcript details
+- Review the [Streaming API](/docs/api-reference/streaming) for real-time transcription