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MoreVoiceDevelopers

Add a participant

POST
/calls/{id}/participants
import { createClient, createResources } from "@morevoice/sdk";


const mv = createResources({
  client: createClient({ baseUrl: "https://api.morevoice.ai/v1", auth: process.env.MOREVOICE_API_KEY }),
});


const callParticipantCreated = await mv.calls.addParticipant("call_IGuHGrBtu5JTm5igG2I8EG", {
  announce: "Joining you to a customer call",
  to: {
    number: "+97235551234",
  },
});
console.log(callParticipantCreated);

Calls handled by a human agent: rings a phone number or an agent into the call (a conference of up to 8), or adds an AI assistant. The participant starts ringing; follow it in GET …/control.

Try it in the API playground with a test-mode key.

Authorizations

Section titled “Authorizations”

Parameters

Section titled “Parameters”

Path Parameters

Section titled “Path Parameters”
id
required
string
<= 200 characters /^call_[0-9A-Za-z]+$/

A call ID (call_…).

Header Parameters

Section titled “Header Parameters”
MoreVoice-Version
string
/^\d{4}-\d{2}-\d{2}$/

The API version to use for this request. Defaults to the version the API key is pinned to.

Example
2026-11-01
Idempotency-Key
string
>= 1 characters <= 255 characters

A unique key (for example a UUID) that makes this request safe to retry: for 24 hours, a retry with the same key and parameters returns the first response instead of acting twice.

Example
5f0c1e8a-7b2d-4c3e-9f1a-2b6d8e4c0a17

Request Bodyrequired

Section titled “Request Bodyrequired”
Media typeapplication/json
object
announce

A line said to them when they join.

string
<= 500 characters
to
required

Who to add: a phone number, an agent or an AI assistant (queues cannot join a call).

object
agent_id

A user ID (usr_…).

string
<= 200 characters /^usr_[0-9A-Za-z]+$/
assistant_id

A assistant ID (asst_…).

string
<= 200 characters /^asst_[0-9A-Za-z]+$/
number
string
/^\+[1-9]\d{6,14}$/
queue_id

A queue ID (q_…).

string
<= 200 characters /^q_[0-9A-Za-z]+$/
Examples
Examplenumber

Ring a phone number in

{
  "announce": "Joining you to a customer call",
  "to": {
    "number": "+97235551234"
  }
}

Responses

Section titled “Responses”

201

Section titled “201”

Created

Media typeapplication/json

A participant being added to a call.

object
call_id
required

A call ID (prefix call_).

string
/^call_[0-9A-Za-z]+$/
name
required
string
object
required
string
Allowed value: call_participant
participant_id
required
string
state
required
string
Allowed values: ringing connected
Example
{
  "call_id": "call_8tRPaZp5hLMbrGqdJ9AmNa",
  "name": "035551234",
  "object": "call_participant",
  "participant_id": "L4f8k2",
  "state": "ringing"
}

400

Section titled “400”

The request is invalid: a parameter is missing, malformed or unknown, or the version header is unknown.

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "parameter_missing",
    "doc_url": "https://docs.morevoice.ai/api/errors#parameter-missing",
    "message": "Missing required parameter: to.",
    "param": "to",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "invalid_request_error"
  }
}

Headers

Section titled “Headers”
X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.

401

Section titled “401”

No valid API key was sent.

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "invalid_api_key",
    "doc_url": "https://docs.morevoice.ai/api/errors#invalid-api-key",
    "message": "Invalid API key.",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "authentication_error"
  }
}

Headers

Section titled “Headers”
X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.

403

Section titled “403”

The key may not do this (a missing scope, a plan limit, or a compliance block).

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "missing_scope",
    "doc_url": "https://docs.morevoice.ai/api/errors#missing-scope",
    "message": "This API key lacks the calls:write scope.",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "permission_error"
  }
}

Headers

Section titled “Headers”
X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.

404

Section titled “404”

No object with this ID exists in this organisation and mode.

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "resource_missing",
    "doc_url": "https://docs.morevoice.ai/api/errors#resource-missing",
    "message": "No such object: 'call_4Gk2'.",
    "param": "id",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "not_found"
  }
}

Headers

Section titled “Headers”
X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.

409

Section titled “409”

The request conflicts with the object’s state, or the Idempotency-Key was reused with other parameters.

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "idempotency_mismatch",
    "doc_url": "https://docs.morevoice.ai/api/errors#idempotency-mismatch",
    "message": "This Idempotency-Key was already used with different parameters.",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "idempotency_error"
  }
}

Headers

Section titled “Headers”
X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.

429

Section titled “429”

Too many requests, or no call capacity right now. Retry after the Retry-After delay.

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "rate_limited",
    "doc_url": "https://docs.morevoice.ai/api/errors#rate-limited",
    "message": "Too many requests. Retry after 1 second.",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "rate_limit_error"
  }
}

Headers

Section titled “Headers”
Retry-After
integer

Seconds to wait before retrying.

X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.

500

Section titled “500”

Something went wrong on MoreVoice’s side. Retry with the same Idempotency-Key.

Media typeapplication/json

Every /v1 error.

object
error
required
object
code
required

A stable, machine-readable code from the error-code catalogue.

string
details

Structured context, e.g. required_scope or the compliance verdict.

object
key
additional properties
doc_url
required

A link to the documentation of this code.

string
message
required

A human-readable explanation. Do not parse it.

string
param

The request parameter the error relates to, e.g. to or metadata[order_id].

string
request_id
required

The X-Request-Id of this request. Quote it when you contact support.

string
type
required

The category of the error.

string
Allowed values: invalid_request_error authentication_error permission_error not_found conflict rate_limit_error compliance_error idempotency_error api_error
Example
{
  "error": {
    "code": "internal_error",
    "doc_url": "https://docs.morevoice.ai/api/errors#internal-error",
    "message": "Something went wrong on MoreVoice's side.",
    "request_id": "req_7Hk2LmN9pQ4rS6tV8wX0yZ",
    "type": "api_error"
  }
}

Headers

Section titled “Headers”
X-Request-Id
string

The request’s ID (req_…). Quote it when you contact support.