Hoiio Open API




app_id* string
Application ID assigned to your application.
access_token* string
Access Token assigned to your application.
msg string
The message that you want to play after the call is answered. Max 1000 characters. Languages and Gender To change the language or gender, use the <speech> markup. E.g. <speech language="zh-HK" gender="female">請稍等,我們正在處理您的訂單。</speech> Default language is English and default gender is Female. For the list of supported language and gender, please refer to Text-to-Speech for more details. Custom Recordings If you would like to use your own voice recordings or voice messages recorded via the Record block, use the <url> markup to specify a file for us to use. We will download the file and use it as the voice message. E.g. <url>https://example.com/myrecording.mp3</url> Only HTTP and HTTPS URL are supported. Supported file formats are .mp3, .wav and .gsm (8000 Hz, mono channel). File size must be 10MB or less. Note: There might be a slight delay when downloading the file for the first time. To enable us to cache your file locally for subsequent calls, please include the "Last-Modified" HTTP header. Subsequent calls will not have the delay if we are able to cache your file. If you have updated your file, make sure your file hosting web server respond to our HTTP header "If-Modified-Since" in our request with a "304 Not Modified".
dest* string
The destination number to call. Phone numbers should start with a "+" and country code (E.164 format), e.g. +6511111111.
caller_id string
This is the Caller ID that the destination number will see on their incoming call. Possible values are: your registered number, your Hoiio Number, "private". Numbers should start with a "+" and country code (E.164 format), e.g. +6511111111. If omitted, your registered number will be used as Caller ID.
max_duration string
The maximum duration of the call (in seconds). The time starts when dest picks up the phone.
ring_time string
The number of seconds to ring the destination before considering the Dial as failed. After ring_time has elapsed, and the call hasn't been answered, the call will be ended. If omitted, the destination will be rung until the call is rejected, or the destination number responds with a No Answer tone.
tag string
This is a text string containing your own reference ID for this transaction. This value will be included in the response for Notification for your reference. Max 256 characters.
notify_url string
A fully-qualified HTTP/S URL on your web server to be notified when this action has completed execution. The length of this parameter must not exceed 4000 characters. See Controlling IVR Behavior for more details. If omitted, the call will hang up after msg is played, and the notification will not be sent to you.

Result Format



There are 2 ways to start an IVR: receive an incoming call at a Hoiio Number or dial out to a destination number. This API dials out to a destination. For incoming calls, please refer to the Answer block.

With this API, specify the voice message and destination number. A call will be made to the destination. After this step is complete, your application will receive another notification for the next course of action. This API can only be used to start a new IVR session. It cannot be used on an ongoing session.

Hoiio API does not support destination to short code, toll free, premium or emergency numbers.

Response Parameters

status The result of your request. Refer to Result Status for details.
session A unique session ID for this particular call. Include this session in your subsequent requests to select what action to take next.
txn_ref A unique reference ID for this call transaction. This parameter will not be present if the request was not successful.

Result Status

success_ok The request has been processed successfully.
error_invalid_http_method Invalid HTTP method. Only GET or POST are allowed.
error_malformed_params HTTP POST request parameters contains non-readable bytes.
error_X_param_missing A required parameter is missing. X is the name of the parameter that is missing.
error_invalid_access_token Your Access Token is invalid, expired or has been revoked.
error_invalid_app_id Your Application ID is invalid or has been revoked.
error_msg_invalid_length Your msg parameter is too long, must be 500 characters or less.
error_msg_cannot_convert_text There was an error converting msg parameter to speech. Make sure you have selected the correct langauge.
error_msg_download_failed There was an error downloading the custom speech file from your URL.
error_msg_invalid_file_format The custom speech file format is not supported or it has the wrong filename extension. Only .mp3, .wav and .gsm files are supported.
error_msg_invalid_file_size The custom speech file size must be 10MB or less.
error_msg_invalid_url The URL for the custom speech file is invalid.
error_msg_invalid_language The language for msg parameter is not supported. For the list of supported languages, please refer to Text-to-Speech for more details.
error_msg_invalid_gender The gender for msg parameter is not supported. For the list of supported genders, please refer to Text-to-Speech for more details.
error_msg_invalid_xml The XML syntax for msg parameter is invalid.
error_tag_invalid_length tag parameter is too long, must be 256 characters or less.
error_invalid_notify_url Invalid URL in notify_url parameter.
error_unable_to_resolve_notify_url Cannot resolve URL in notify_url parameter.
error_unable_to_complete_ssl_handshake_notify_url Cannot complete SSL Handshake with the provided URL in notify_url parameter. Check if your cert chain is complete using an SSL checker.
error_invalid_session The session is invalid.
error_dest_invalid dest parameter is invalid.
error_dest_not_supported Calling to this destination is currently not supported.
error_max_duration_invalid The provided max_duration is not a integer, or it is negative.
error_ring_time_invalid The provided ring_time is not a integer, or it is negative.
error_not_allowed_for_trial Destination number not supported for trial accounts. To remove this restriction, please make a credit top-up. See Free Trial for details and supported numbers.
error_caller_id_invalid caller_id parameter is invalid.
error_insufficient_credit You have insufficient credit in your developer account to make this call.
error_concurrent_call_limit_reached You have exceeded the maximum number of concurrent calls. Each account is allowed only 8 active calls at any point of time.
error_call_service_not_available There are problems initiating your call request. Please try again in a few minutes.
error_rate_limit_exceeded You have exceeded your request limit for this API. Refer to API Limits for details.
error_internal_server_error There is an unexpected error. Please contact Hoiio support for assistance.


You will receive a notification to your application URL when the Dial block has finished executing with the following parameters:

Notification Parameters

ivr_block This is an identifer for the type of block this notification is for. You can use this to differenciate between notifications. This block notification can be identified by the value dial.
session This is a unique session ID for this particular call. Include this session in your subsequent requests to select what action to take next.
txn_ref The unique reference ID for this transaction.
dest The destination number that was called. Phone numbers start with a "+" and country code (E.164 format), e.g. +6511111111.
tag Your own reference ID submitted in the initial Dial requests.
call_state The current state of this call. Possible values are:
  • ongoing - This call has been answered. You should follow up with one of the Middle or End blocks.
  • ended - This call has ended. You should not send any more requests for this call.
dial_status Dial status of for the call to dest. Possible values are:
  • answered
  • unanswered
  • failed
  • busy
date Date/time (GMT+8) of this transaction in "YYYY-MM-DD HH:mm:SS" format. This is present only if call_state=ended.
duration Duration of the call in minutes. This is present only if call_state=ended.
currency Currency used for this transaction. Refer to Currency Code for the list of currency code. This is present only if call_state=ended.
rate Per-minute charges (sum of both incoming and outgoing call rates) for this call transaction. This is present only if call_state=ended.
debit Total amount billed for this transaction. This is present only if call_state=ended.

API Limits

Maximum of 8 active call per application at any point of time


You will be charged the outgoing call rate depending on the country of the destination number.

If you use the Transfer block later on in this call, an additional outgoing call rate (depending on the destination number of the transfer) will be charged. For details of the incoming and outgoing call rate, please refer to the Pricing Section.