External Infrastructure Integration Guide

Pranthora Voice Platform — Client Integration Reference

Overview

Pranthora supports connecting your own telephony or audio infrastructure directly to the platform. Once connected, Pranthora handles the full AI pipeline — speech recognition, LLM inference, and text-to-speech — and streams responses back to your infrastructure in real time. Two integration modes are supported:

Mode	Best For
Pure WebSocket	SIP/media servers, custom telephony infrastructure, real-time audio bridges
HTTP + WebSocket	Systems that need a session handshake before opening a persistent stream

Authentication

All external connections authenticate using an API Key generated from the Pranthora platform.

Generate your API key from Pranthora Dashboard → Settings → API Keys

How to pass the API Key

For both integration modes, set the API key in the WebSocket connection header:

x-api-key: <your-api-key>

Pranthora extracts and validates the key on every new WebSocket connection. Connections without a valid key will be rejected with close code 4001.

Integration Mode 1 — Pure WebSocket

In this mode, your infrastructure connects directly to the Pranthora WebSocket endpoint, streams audio, and receives AI-generated speech in return. No prior HTTP handshake is needed.

Connection

wss://<pranthora-host>/api/call/web-media-stream?agent_id=<agent_id>

Or, if using a workflow instead of a single agent:

wss://<pranthora-host>/api/call/web-media-stream?workflow_id=<workflow_id>

Required query parameters — one of:

Parameter	Type	Description
`agent_id`	string	ID of the agent to connect to
`workflow_id`	string	ID of the workflow to connect to

Required headers:

Header	Value
`x-api-key`	Your API key

Connection Lifecycle

Your Infra                          Pranthora
    |                                   |
    |------- WebSocket Upgrade -------->|  (includes x-api-key header)
    |<------ 101 Switching Protocols ---|
    |                                   |
    |<-- {"event_type": "start_media_streaming"} (text frame)
    |                                   |  ← signal: begin sending audio
    |------- raw PCM audio bytes ------>|  (binary frames, continuous)
    |------- raw PCM audio bytes ------>|
    |------- raw PCM audio bytes ------>|
    |                                   |
    |<------ raw PCM audio bytes -------|  (TTS response, binary frames)
    |<------ raw PCM audio bytes -------|
    |                                   |
    |<---------- "stop" (text frame) ---|  (interruption signal)
    |                                   |  ← your infra must stop playback
    |------- raw PCM audio bytes ------>|  (user continues speaking)
    |                                   |
    |<------ raw PCM audio bytes -------|  (new TTS response)
    |                                   |
    |------- WebSocket Close ---------->|  (end of call)

Sending Audio (Client → Pranthora)

Wait for the {"event_type": "start_media_streaming"} text frame before sending audio.
Send audio as raw binary frames (no envelope, no JSON wrapper).
Stream continuously in small chunks — do not buffer or batch large chunks.

Expected audio format:

Property	Value
Encoding	PCM (Linear 16-bit, little-endian)
Sample Rate	16,000 Hz
Channels	1 (mono)
Frame Type	WebSocket binary frame

Receiving from Pranthora (Pranthora → Client)

Pranthora sends two types of frames back to your connection:

TTS Audio — Binary Frame

Raw PCM audio bytes in the same format as the inbound audio (16kHz, mono, PCM). Play this directly to the end user.

Interruption Signal — Text Frame

stop

When you receive this text frame, immediately halt playback of any TTS audio you are currently streaming to the user. The user has spoken and Pranthora is generating a new response. Discard any buffered TTS audio.

Session Timeout

Pranthora enforces a configurable session timeout on idle connections. When the timeout is reached, the WebSocket will be closed with code 1000 and reason "Session timeout reached". Your infrastructure should reconnect if the call is still active.

Integration Mode 2 — HTTP Handshake + WebSocket

In this mode, your infrastructure sends a single HTTP request to Pranthora with your API key. Pranthora authenticates the request and returns a WebSocket URL. Your infrastructure then connects to that URL and begins streaming audio. This is useful for systems where a request/response handshake is required before opening a persistent connection — for example, orchestration layers that need to know the target URL before instructing a media server to connect.

Step 1 — Request a WebSocket URL

POST https://<pranthora-host>/api/call
x-api-key: <your-api-key>
Content-Type: application/json

{
  "agent_id": "<agent_id>"
}

Or using a workflow:

POST https://<pranthora-host>/api/call
x-api-key: <your-api-key>
Content-Type: application/json

{
  "workflow_id": "<workflow_id>"
}

Response:

{
  "websocket_url": "wss://<pranthora-host>/api/call/media-stream/agents/<agent_id>"
}

Pranthora validates the API key and, if authenticated, returns the WebSocket URL your infrastructure should connect to.

Step 2 — Connect via WebSocket

Connect to the websocket_url returned in Step 1 using the Telephony Protocol (JSON-framed messages). The full message protocol is described in the Telephony Protocol section below.

wss://<pranthora-host>/api/call/media-stream/agents/<agent_id>

Telephony Protocol (Twilio-Compatible)

If your infrastructure is a telephony provider or SBC that supports the Twilio Media Streams protocol, you can connect to the dedicated telephony WebSocket endpoints. This protocol uses JSON-framed messages instead of raw binary frames, and operates at 8kHz with mulaw encoding — matching traditional telephony.

Connection

Per-agent:

wss://<pranthora-host>/api/call/media-stream/agents/<agent_id>

Per-workflow:

wss://<pranthora-host>/api/call/media-stream/workflows/<workflow_id>

These endpoints follow the Twilio Media Streams WebSocket protocol. Your infrastructure must send and receive Twilio-format JSON events.

Message Protocol

All messages are UTF-8 encoded JSON text frames.

Client → Pranthora

Start Event — sent once when the stream begins:

{
  "event": "start",
  "start": {
    "streamSid": "<unique-stream-id>",
    "callSid": "<call-identifier>"
  }
}

Media Event — sent continuously with audio chunks:

{
  "event": "media",
  "media": {
    "payload": "<base64-encoded-audio>"
  }
}

Stop Event — sent when the call ends:

{
  "event": "stop"
}

Pranthora → Client

TTS Audio:

{
  "event": "media",
  "streamSid": "<stream-id>",
  "media": {
    "payload": "<base64-encoded-tts-audio>"
  }
}

Interruption / Clear Buffer:

{
  "event": "clear",
  "streamSid": "<stream-id>"
}

Upon receiving clear, stop playback immediately and flush any buffered TTS audio. TTS Completion Mark:

{
  "event": "mark",
  "streamSid": "<stream-id>",
  "mark": {
    "name": "tts_completed"
  }
}

Signals that the current TTS utterance has finished sending. Useful for synchronizing playback end detection on your side.

Supported Audio Formats

Format	Sample Rate	Encoding	Frame Type	Integration Mode
PCM Linear 16-bit	16,000 Hz	Raw PCM (little-endian)	Binary	Pure WebSocket / HTTP+WS
mulaw (µ-law)	8,000 Hz	Base64 (JSON-wrapped)	Text (JSON)	Telephony Protocol
alaw (A-law)	8,000 Hz	Base64 (JSON-wrapped)	Text (JSON)	Telephony Protocol

Note: Resampling is handled internally. If you send 8kHz mulaw audio, Pranthora upsamples it to 16kHz for model processing. TTS output is likewise encoded and downsampled back to match your input format.

Interruption Handling

Pranthora’s voice pipeline includes real-time interruption detection. When the system detects that the user is speaking while the agent is responding:

Any in-progress TTS generation is cancelled.
Pranthora sends an interruption signal to your connection:
- Pure WebSocket: text frame "stop"
- Telephony Protocol: {"event": "clear", "streamSid": "..."}
Your infrastructure must stop playback and discard any buffered audio.
Pranthora processes the new user speech and sends a fresh response.

Interruptions are validated intelligently — filler sounds like “um”, “uh”, or “hmm” do not trigger an interruption, but clear speech ("wait", "stop", "actually", direct questions, etc.) will.

WebSocket Close Codes

Code	Reason	Action
`1000`	Normal closure / Session timeout / Call terminated by agent	Close gracefully
`4001`	Invalid origin or unauthorized	Check `x-api-key` header
`4002`	Missing `agent_id` or `workflow_id`	Add required query parameter
`4003`	Agent/workflow not found	Verify the ID is correct
`1008`	Missing required parameter	Check connection parameters
`1011`	Session not found	Re-authenticate and reconnect

Quick Reference

Pure WebSocket

wss://<host>/api/call/web-media-stream?agent_id=<id>
Header: x-api-key: <key>

Wait for: {"event_type": "start_media_streaming"}
Send:     raw binary PCM frames (16kHz, mono)
Receive:  raw binary PCM frames (TTS) | text "stop" (interruption)

HTTP + WebSocket

POST https://<host>/api/call
Header: x-api-key: <key>
Body:   {"agent_id": "<id>"}
→ {"websocket_url": "wss://<host>/api/call/media-stream/agents/<id>"}

Connect to returned websocket_url → use Telephony Protocol (JSON events)

Telephony Protocol

wss://<host>/api/call/media-stream/agents/<agent_id>

Send:     JSON events — start / media / stop
Receive:  JSON events — media (TTS) / clear (interrupt) / mark (TTS done)
Audio:    8kHz mulaw or alaw, base64-encoded inside JSON

Get Started

Assistants

Voice Workflows

Integrations

Text Agents

Outbound

External infrastructure integration guide

External Infrastructure Integration Guide

Overview

Authentication

How to pass the API Key

Integration Mode 1 — Pure WebSocket

Connection

Connection Lifecycle

Sending Audio (Client → Pranthora)

Receiving from Pranthora (Pranthora → Client)

TTS Audio — Binary Frame

Interruption Signal — Text Frame

Session Timeout

Integration Mode 2 — HTTP Handshake + WebSocket

Step 1 — Request a WebSocket URL

Step 2 — Connect via WebSocket

Telephony Protocol (Twilio-Compatible)

Connection

Message Protocol

Client → Pranthora

Pranthora → Client

Supported Audio Formats

Interruption Handling

WebSocket Close Codes

Quick Reference

Pure WebSocket

HTTP + WebSocket

Telephony Protocol

​External Infrastructure Integration Guide

​Overview

​Authentication

​How to pass the API Key

​Integration Mode 1 — Pure WebSocket

​Connection

​Connection Lifecycle

​Sending Audio (Client → Pranthora)

​Receiving from Pranthora (Pranthora → Client)

​TTS Audio — Binary Frame

​Interruption Signal — Text Frame

​Session Timeout

​Integration Mode 2 — HTTP Handshake + WebSocket

​Step 1 — Request a WebSocket URL

​Step 2 — Connect via WebSocket

​Telephony Protocol (Twilio-Compatible)

​Connection

​Message Protocol

​Client → Pranthora

​Pranthora → Client

​Supported Audio Formats

​Interruption Handling

​WebSocket Close Codes

​Quick Reference

​Pure WebSocket

​HTTP + WebSocket

​Telephony Protocol

External Infrastructure Integration Guide

Overview

Authentication

How to pass the API Key

Integration Mode 1 — Pure WebSocket

Connection

Connection Lifecycle

Sending Audio (Client → Pranthora)

Receiving from Pranthora (Pranthora → Client)

TTS Audio — Binary Frame

Interruption Signal — Text Frame

Session Timeout

Integration Mode 2 — HTTP Handshake + WebSocket

Step 1 — Request a WebSocket URL

Step 2 — Connect via WebSocket

Telephony Protocol (Twilio-Compatible)

Connection

Message Protocol

Client → Pranthora

Pranthora → Client

Supported Audio Formats

Interruption Handling

WebSocket Close Codes

Quick Reference

Pure WebSocket

HTTP + WebSocket

Telephony Protocol