Documentation Index
Fetch the complete documentation index at: https://docs.nixflex.com/llms.txt
Use this file to discover all available pages before exploring further.
Configure a webhook URL on an agent and Nixflex will POST the call data to your server after every call. Use this to sync transcripts to your database, trigger downstream workflows, or pipe events into Zapier / Make.
Setting a webhook
Set webhook_url when creating or updating an agent:
curl -X PUT https://api.nixflex.com/v1/agents/agent_xxx \
-H "Authorization: Bearer KEY_ID:KEY_SECRET" \
-H "Content-Type: application/json" \
-d '{"webhook_url": "https://api.yourapp.com/nixflex/calls"}'
Payload structure
You receive a JSON body like this:
{
"event": "call.ended",
"call_id": "CA1234567890",
"agent_id": "agent_125207e452f8714a",
"direction": "inbound",
"from_number": "+447386172392",
"to_number": "+447446466847",
"started_at": "2026-05-17T03:45:12Z",
"ended_at": "2026-05-17T03:47:38Z",
"duration_seconds": 146,
"ended_reason": "agent_hangup",
"transcript": [
{ "role": "agent", "text": "Hello, Acme Dental, how can I help?", "timestamp_ms": 1200 },
{ "role": "caller", "text": "Hi, I'd like to book a check-up.", "timestamp_ms": 3800 }
],
"recording_url": "https://storage.nixflex.com/recordings/CA1234567890.mp3",
"call_summary": "Caller booked a check-up for Tuesday 8th March at 2pm.",
"caller_sentiment": "happy",
"call_successful": true,
"extracted_data": {
"caller_name": "Sarah Johnson",
"appointment_date": "2026-03-08",
"appointment_time": "14:00"
},
"metadata": {}
}
metadata echoes whatever you passed when creating an outbound call. Useful for tying calls back to records in your own system (order IDs, customer IDs, etc.).
Event types
| Event | When |
|---|
call.ended | After post-call analysis completes |
call.failed | Call failed before connection (Twilio error, agent not found, etc.) |
sms.delivered | SMS sent via Nixflex was confirmed delivered by Twilio |
sms.received | A new SMS came in to one of your numbers |
call.ended. Other events are optional — check the event field if you want to handle multiple.
Signing and verification
Every webhook request includes a signature header so you can verify it came from Nixflex:
X-Nixflex-Signature: t=1715900000,v1=abc123...
const crypto = require('crypto');
function verifyNixflexSignature(rawBody, signatureHeader, secret) {
const [timestamp, sig] = signatureHeader.split(',').map(p => p.split('=')[1]);
const payload = `${timestamp}.${rawBody}`;
const expected = crypto
.createHmac('sha256', secret)
.update(payload)
.digest('hex');
return crypto.timingSafeEqual(
Buffer.from(sig),
Buffer.from(expected)
);
}
Always verify webhook signatures in production. Without verification, anyone who knows your URL could spam your endpoint with fake data.
Retries
If your endpoint:
- Returns 2xx — webhook is considered delivered, no retry
- Returns 4xx or 5xx — Nixflex retries with exponential backoff
- Times out (>10s) — counted as a failure, retried
Retry schedule: 1 minute, 5 minutes, 30 minutes, 2 hours, 12 hours. After 5 failed attempts the webhook is given up on.
You can see delivery attempts in the dashboard under the agent’s Webhook tab.
Idempotency
Each webhook delivery includes a unique webhook_delivery_id header. Same call_id may arrive twice if a retry succeeds after the original was actually delivered — your endpoint should be idempotent.
Pattern: store the webhook_delivery_id and skip if you’ve seen it before.
Connecting to Zapier / Make
Both platforms support generic webhook triggers. Point them at the Nixflex webhook URL Zapier/Make gives you, and every call becomes a trigger. From there, send transcripts to:
- Google Sheets
- HubSpot / Salesforce / GoHighLevel
- Slack / Discord / Microsoft Teams
- Notion / Airtable
- Email (Gmail, Mailgun)
- Anything else Zapier supports (7,000+ apps)
Testing your webhook
In the dashboard under your agent’s Webhook tab, click Send test event. You’ll get a synthetic payload at your URL with realistic data so you can verify your handler works before live calls hit it.
