Zernio
Zernio
API Reference

Voice & Calling

Calls

List phone callsGETPlace an outbound phone callPOSTGet a phone callGETHang up a live callPOSTBlind-transfer a live callPOSTGet a call recordingGETEstimate call costGET

Browser Softphone

Mint a browser softphone sessionPOSTDial from the browser softphonePOST

Number Setup

Enable phone calling on a numberPOSTDisable phone calling on a numberDELETEAttach a number to a SIP trunkPOSTDetach a number from its SIP trunkDELETE

SIP Trunks

List SIP trunksGETCreate a SIP trunkPOSTGet a SIP trunkGETDelete a SIP trunkDELETERotate a SIP trunk's passwordPOST
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Voice & Calling

List phone calls

Your PSTN voice calls (inbound + outbound), newest first. Cursor pagination: pass the returned nextCursor as before for the next page. For a history that also includes WhatsApp calls, use GET /v1/calls.

GET
/v1/voice/calls

Authorization

bearerAuth
AuthorizationBearer <token>

API key authentication: send your Zernio API key in the Authorization header, prefixed with Bearer.

In: header

Query Parameters

status?string

Value in

  • "ringing"
  • "answered"
  • "ended"
  • "failed"
direction?string

Value in

  • "inbound"
  • "outbound"
number?string

Exact filter: calls involving this number (typically one of your DIDs). E.164, leading + optional.

before?string
Formatdate-time
limit?integer
Range1 <= value <= 200
Default50

Response Body

application/json

application/json

import Zernio from '@zernio/node';const zernio = new Zernio({ apiKey: process.env.ZERNIO_API_KEY });const { data } = await zernio.voice.listVoiceCalls();console.log(data);
{  "calls": [    {      "_id": "string",      "accountId": "string",      "conversationId": "string",      "contactId": "string",      "channel": "whatsapp",      "direction": "inbound",      "from": "string",      "to": "string",      "forwardTo": "string",      "greeting": "string",      "status": "ringing",      "isVoicemail": true,      "amd": true,      "answeredMachine": true,      "forwardCallerId": "business",      "recordingEnabled": true,      "transcriptionEnabled": true,      "transcriptionLanguage": "auto",      "startedAt": "2019-08-24T14:15:22Z",      "answeredAt": "2019-08-24T14:15:22Z",      "endedAt": "2019-08-24T14:15:22Z",      "transferredAt": "2019-08-24T14:15:22Z",      "durationSeconds": 0,      "endReason": "hangup",      "hangupCause": "string",      "sipHangupCause": "string",      "callErrors": [        {          "code": 0,          "message": "string"        }      ],      "recordingUrl": "string",      "lastTranscriptSnippet": "string",      "transcript": [        {          "text": "string",          "confidence": 0,          "at": "2019-08-24T14:15:22Z"        }      ],      "billing": {        "metaMinutes": 0,        "telnyxSeconds": 0,        "transcriptionSeconds": 0,        "transcriptionCostUSD": 0,        "metaCostUSD": 0,        "telnyxCostUSD": 0,        "recordingCostUSD": 0,        "billableCostUSD": 0,        "totalCostUSD": 0,        "currency": "string"      },      "createdAt": "2019-08-24T14:15:22Z",      "updatedAt": "2019-08-24T14:15:22Z"    }  ],  "nextCursor": "2019-08-24T14:15:22Z"}
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Get a call (any channel)

Channel-agnostic call detail: works for both WhatsApp and regular phone (PSTN) calls, so any row from `GET /v1/calls` can be opened without branching on `channel`. Returns the full call including transcript segments, with `contactId`/`contactName` set when the counterparty matches a CRM contact.

Place an outbound phone call

Dials `to` FROM one of your voice-enabled numbers and, on answer, bridges the callee to the number's stored forward destination, or to the per-call `forwardTo` override. Destinations can be your own AI voice agent (Vapi/Retell), a phone, or a SIP endpoint. An optional `greeting` is spoken to the callee before the bridge. The 200 response means the call is dialing; the lifecycle continues asynchronously (track it via `GET /v1/voice/calls/{id}` or the `call.*` webhooks). Outbound calls are capped per rolling hour (429 when hit). **Idempotency:** send an `Idempotency-Key` header to make retries safe; same key + same body replays the original response instead of dialing (and billing) a second call.