When to Use This Skill
- Setting up Deepgram callback handlers for transcription results
- Processing asynchronous transcription results from Deepgram
- Implementing webhook authentication for Deepgram callbacks
- Handling transcription completion events
Essential Code
Deepgram webhooks (callbacks) are used to receive transcription results asynchronously. When you provide a callback URL in your transcription request, Deepgram immediately responds with a request_id and sends the transcription results to your callback URL when processing is complete.
Basic Webhook Handler
// Express.js example
const crypto = require('crypto');
function safeEqual(a, b) { const ab = Buffer.from(a || '', 'utf8'); const bb = Buffer.from(b || '', 'utf8'); return ab.length === bb.length && crypto.timingSafeEqual(ab, bb); }
app.post('/webhooks/deepgram', express.raw({ type: 'application/json' }), (req, res) => { // 1. Primary check: Basic Auth credentials you embedded in the callback URL // (https://user:pass@your-domain.com/webhooks/deepgram) const auth = req.headers['authorization'] || ''; const decoded = auth.startsWith('Basic ') ? Buffer.from(auth.slice(6), 'base64').toString('utf8') : ''; const sep = decoded.indexOf(':'); if ( sep === -1 || !safeEqual(decoded.slice(0, sep), process.env.DEEPGRAM_CALLBACK_USERNAME) || !safeEqual(decoded.slice(sep + 1), process.env.DEEPGRAM_CALLBACK_PASSWORD) ) { return res.status(401).send('Unauthorized'); }
// 2. Supplementary check: dg-token is NOT sent on every callback, // so only compare it when it is present const dgToken = req.headers['dg-token']; if (dgToken && process.env.DEEPGRAM_API_KEY_ID && !safeEqual(dgToken, process.env.DEEPGRAM_API_KEY_ID)) { return res.status(403).send('Invalid dg-token'); }
// The callback body is the normal /v1/listen response: { metadata, results } const payload = JSON.parse(req.body.toString()); const requestId = payload.metadata?.request_id; const transcript = payload.results?.channels?.[0]?.alternatives?.[0]?.transcript; console.log('Received transcription:', requestId, transcript);
// Return success to prevent retries res.status(200).send('OK'); });
### Authentication Methods
Deepgram documents two ways to authenticate callbacks:
1. **Basic Auth (primary)**: Embed credentials in the callback URL; Deepgram sends them as an `Authorization: Basic` header
2. **dg-token Header (supplementary)**: When present, contains the API Key Identifier of the key that submitted the request. Deepgram's docs state it "is not guaranteed on every callback request", so never rely on it alone
```javascript
// Basic Auth in callback URL (percent-encode special characters in the credentials)
// https://username:password@your-domain.com/webhooks/deepgram
// dg-token: check only when present
const dgToken = req.headers['dg-token'];
if (dgToken && dgToken !== process.env.DEEPGRAM_API_KEY_ID) {
return res.status(403).send('Invalid dg-token');
}
Making a Request with Callback
curl \
--request POST \
--header 'Authorization: Token YOUR_DEEPGRAM_API_KEY' \
--header 'Content-Type: audio/wav' \
--data-binary @audio.wav \
--url 'https://api.deepgram.com/v1/listen?callback=https://username:password@your-domain.com/webhooks/deepgram'
Common Event Types
Deepgram callbacks carry no event-type field. The body is the same JSON a synchronous /v1/listen request returns: a metadata object and a results object. The structure of results varies based on the features enabled in your request:
| Field | Description | Always Present |
|---|---|---|
metadata.request_id |
Unique identifier for the transcription request (matches the request_id returned when you submitted it) |
Yes |
metadata.created |
Timestamp when transcription was created | Yes |
metadata.duration |
Length of the audio in seconds | Yes |
metadata.channels |
Number of audio channels | Yes |
metadata.extra |
Key-value pairs you passed with extra=KEY:VALUE |
Only if extra was sent |
results.channels[].alternatives |
Transcription alternatives | Yes |
results.channels[].alternatives[].transcript |
The transcribed text | Yes |
results.channels[].alternatives[].confidence |
Confidence score (0-1) | Yes |
Environment Variables
# Your Deepgram API Key (for making requests)
DEEPGRAM_API_KEY=your_api_key_here
# Basic Auth credentials you embed in the callback URL (primary check)
DEEPGRAM_CALLBACK_USERNAME=your_callback_username
DEEPGRAM_CALLBACK_PASSWORD=your_callback_password
# Optional: API Key Identifier, used to check the dg-token header when present
# Note: This is NOT your API Key secret - it's a unique identifier shown
# in the Deepgram console that identifies which API key was used for a request
DEEPGRAM_API_KEY_ID=your_api_key_id_here
# Your webhook endpoint URL
WEBHOOK_URL=https://your-domain.com/webhooks/deepgram
Local Development
For local webhook testing, install Hookdeck CLI:
# Create a local tunnel (no account required)
npx hookdeck-cli listen 3000 deepgram --path /webhooks/deepgram
# Use the provided URL as your callback URL when making Deepgram requests
This provides:
- Local tunnel URL for testing
- Web UI for inspecting webhook payloads
- Request history and debugging tools
Important Notes
Retry Behavior
- Deepgram retries failed callbacks (non-200-299 status) up to 10 times
- 30-second delay between retry attempts
- Always return 200-299 status for successfully processed webhooks
Port Restrictions
- Only ports 80, 443, 8080, and 8443 are allowed for callbacks
- Ensure your webhook endpoint uses one of these ports
No Signature Verification
- Deepgram does not sign callbacks (no HMAC, no timestamp)
- Authenticate with Basic Auth credentials embedded in the callback URL; treat the
dg-tokenheader as a supplementary check because it is not sent on every callback - Always use HTTPS for webhook endpoints
Resources
- overview.md - What Deepgram webhooks are, transcription events
- setup.md - Configure callbacks in Deepgram API requests
- verification.md - Authentication methods and security considerations
- examples/ - Complete implementations for Express, Next.js, and FastAPI
Recommended: webhook-handler-patterns
For production handlers, install the patterns skill alongside this one. Key references (links work when only this skill is installed):
Related Skills
- stripe-webhooks - Stripe payment webhooks
- shopify-webhooks - Shopify store webhooks
- github-webhooks - GitHub repository webhooks
- webhook-handler-patterns - Idempotency, error handling, retry logic
- hookdeck-event-gateway - Webhook infrastructure that replaces your queue — guaranteed delivery, automatic retries, replay, rate limiting, and observability for your webhook handlers