Stringee Call API Overview

The Stringee Call API is the easiest way to build high-quality voice applications in the Cloud. With the Stringee Call API you:

Build apps that scale with the web technologies that you are already using
Dynamically buy phone numbers
Extend your infrastructure with SIP Interface
Control the flow of calls in JSON with Stringee Call Control Objects (SCCO):
- Make an app-to-app call (peer-to-peer call) OR app-to-phone call (outbound call)
- Receive and handle a phone call (inbound call): transfer call to app, reject call, record, ...
Record and store calls
Create conference calls

Concepts

Authentication with JWT: interaction with the Stringee Server are authenticated using JWTs (JSON Web Tokens format): https://jwt.io
SCCO: Stringee Call Control Objects are a set of actions that instruct the Stringee how to control call to/from your Client application/your Number. For example, you can connect a call, transfer a call, or record a call.
answer_url: the URL where Your Server delivers the SCCO.
event_url: Stringee Server sends event information asynchronously to this URL when call status changes.

Client authentication

In order to make or receive a call using Stringee API, your Client application must be authenticated. The authentication process is implemented between: Your App, Your Server and Stringee Server. It ensures the system's security (secret key is not stored on the client) and allows Your Server to block or unblock any client whenever you want.

Authentication process is described here: https://developer.stringee.com/docs/client-authentication

How Stringee Call works (some flows)

Flow 1: Make an app-to-app call

Use Stringee Call API to embed app-to-app voice or video, follow these steps:

Stringee Make an app-to-app call

Your App calls the makeCall(from, to) method: "from" is the caller's ID (user_1), "to" is the called party's ID (user_2).
Stringee Server gets SCCO from Your Server by sending a HTTP GET via answer_url (answer_url must be configed in your Project on https://developer.stringee.com), for example:

https://yourserver.com/answer_url-from_internal.php?from=user_1&to=user_2&fromInternal=true&userId=user_1&projectId=22512&callId=call-vn-1-ABCDWXKUQM-1542377678921&custom=

Your Server returns SCCO in following format:

[{
  "action": "connect",

  "from": {
    "type": "internal",
    "number": "user_1",
    "alias": "user_1"
  },

  "to": {
    "type": "internal",//internal: app-to-app call type
    "number": "user_2",//make a call to user_2
    "alias": "user_2",
  },

  "customData": "test-custom-data"
}]

Flow 2: Make an app-to-phone call

Use Stringee Call API to make and control calls between mobile or web apps and landline or mobile phones, follow these steps:

Stringee Make an app-to-phone call

Your App calls the makeCall(from, to) method: "from" is your number (phone_number_1) which will be displayed to called party, "to" is the called party's number (phone_number_2).
Stringee Server gets SCCO from Your Server by sending a HTTP GET via answer_url (answer_url must be configed in your Project on https://developer.stringee.com), for example:

https://yourserver.com/answer_url-from_internal.php?from=phone_number_1&to=phone_number_2&fromInternal=true&userId=user_1&projectId=22512&callId=call-vn-1-ABCDWXKUQM-1542377678921&custom=

Your Server returns SCCO in following format:

[{
  "action": "connect",

  "from": {
    "type": "internal",
    "number": "phone_number_1",//the phone number that displayed to the called party.
    "alias": "phone_number_1"
  },

  "to": {
    "type": "external",//external: app-to-phone call type
    "number": "phone_number_2",//make a call to this phone number
    "alias": "phone_number_2",
  },

  "customData": "test-custom-data"
}]

Flow

Flow 3: Receive a phone call

Use Stringee Call API to route a phone call to Your App, follow these steps:

Stringee Receive a phone call

Your phone number (phone_number_1) which bought from Stringee receives a phone call (for example from a your customer).
Stringee Server gets SCCO from Your Server by sending a HTTP GET via answer_url (answer_url must be configed in your Number on https://developer.stringee.com), for example:

https://yourserver.com/answer_url-from_external.php?from=phone_number_2&to=phone_number_1&uuid=882696e2-bb01-11e7-8056-3fae8fb0a1ad&callId=call-vn-1-ABCDWXKUQM-1542377678921&fromInternal=false

Your Server returns SCCO in following format:

[{
    "action": "connect",

    "from": {
        "type": "external",
        "number": "phone_number_2",//the caller's phone number
        "alias": "phone_number_2"
    },

    "to": {
        "type": "internal",//internal: the call is routed to Your App
        "number": "user_1",// the call is routed to this user.
        "alias": "phone_number_1"//your phone number which bought from Stringee
    },

    "customData": "test-custom-data"
}]

Flow

Flow 4: Receive a phone call and route to phone

Use Stringee Call API to route a phone call to phone, follow these steps: