Telephony — Overview - rapida.ai documentation

The assistant-api supports five telephony providers. Each is identified by a string constant defined in api/assistant-api/internal/channel/telephony/telephony.go.

const (
    Twilio   Telephony = "twilio"
    Exotel   Telephony = "exotel"
    Vonage   Telephony = "vonage"
    Asterisk Telephony = "asterisk"
    SIP      Telephony = "sip"
)

Provider Comparison

Provider	Transport	Audio Format	Region
Twilio	WebSocket (Media Streams)	μ-law 8kHz	Global
Vonage	WebSocket	Linear PCM 16kHz	Global
Exotel	WebSocket	μ-law 8kHz	India / SEA
Asterisk AudioSocket	Raw TCP `0.0.0.0:4573`	Linear PCM 8kHz	Self-hosted PBX
Asterisk WebSocket	WebSocket (`chan_websocket`)	μ-law 8kHz	Self-hosted PBX
SIP	UDP `0.0.0.0:5090` + RTP	PCM	Direct SIP / SIP trunks

Twilio, Vonage, and Exotel are cloud providers — they call your server. You need PUBLIC_ASSISTANT_HOST set to a public HTTPS hostname (use ngrok locally).Asterisk AudioSocket and WebSocket run on your own PBX — Asterisk connects out to Rapida.SIP is a built-in server in assistant-api — any SIP client can call it directly.

URL Routing Pattern

All telephony paths follow this structure (source: api/assistant-api/internal/type/telephony.go):

// Inbound call webhook — provider calls this when a call arrives
func GetContextAnswerPath(provider, contextID string) string {
    return fmt.Sprintf("v1/talk/%s/ctx/%s", provider, contextID)
    // Example: v1/talk/twilio/ctx/abc-123
}

// Status / event callback
func GetContextEventPath(provider, contextID string) string {
    return fmt.Sprintf("v1/talk/%s/ctx/%s/event", provider, contextID)
    // Example: v1/talk/twilio/ctx/abc-123/event
}

Path	Method	Purpose
`/v1/talk/{provider}/call/{assistantId}`	POST / GET	Inbound call webhook (provider → Rapida)
`/v1/talk/{provider}/ctx/{contextId}`	WebSocket	Bidirectional audio stream
`/v1/talk/{provider}/ctx/{contextId}/event`	POST	Status / lifecycle events

The contextId is created on the first webhook hit and binds the conversation to a provider session. It is stored in PostgreSQL with the assistant ID, conversation ID, and auth token.

Inbound Call Flow

What’s Next

Running with a Provider

Step-by-step setup for Twilio, Vonage, Exotel, Asterisk AudioSocket, Asterisk WebSocket, and SIP.

Adding a New Provider

Implement the Telephony interface and register a new provider in the factory.

ngrok — Local Testing

Expose your local Rapida instance to Twilio, Vonage, and Exotel for development.

Configuration

All env vars: PUBLIC_ASSISTANT_HOST, SIP, AudioSocket, and more.

Getting Started

Dashboard (UI)

Web API

Assistant API

Integration API

Endpoint API

Document API

Telephony — Overview

Provider Comparison

URL Routing Pattern

Inbound Call Flow

What’s Next

Running with a Provider

Adding a New Provider

ngrok — Local Testing

Configuration

​Provider Comparison

​URL Routing Pattern

​Inbound Call Flow

​What’s Next

Running with a Provider

Adding a New Provider

ngrok — Local Testing

Configuration

Provider Comparison

URL Routing Pattern

Inbound Call Flow

What’s Next