To be able to receive incoming calls, you need to setup your push certificate in the Console and your app needs to register for incoming calls using Voice.register(...). Twilio will send you a high-priority push notification through FCM (Firebase Cloud Messaging Service). Check our quickstart implementation for how it is done.
GCM (Google Cloud Messaging Service) was deprectated by Google on April 10, 2018. If you are currently using GCM, please migrate to FCM. GCM issues are not supported at this time.
Yes! See How can my App receive calls to register for incoming calls. Once the app is registered, it will receive incoming call push notifications even when it's in the background or not running.
The device token must be registered every time it changes or if the device has not received a push notification for one year. We recommend you implement the following logic:
FirebaseMessagingService
and check when the token is updated or invalidated via
onNewToken()
callback. Compare it to the token value stored in step two, above. If it has changed, invoke
Voice.register(...)
and store the new device token value.
An Access Token is required to access Twilio's services. A device token is a token that identifies the device to receive a push notification.
Below are several troubleshooting steps to make sure you have set up your application to receive push notifications:
VoiceGrant
. Twilio Access Token supports authentication for multiple products, but you must use a
VoiceGrant
with the Programmable Voice SDK.
identity
.
Below are troubleshooting steps if you are not receiving incoming call push notifications even if the SDK is successfully registered:
FCM SECRET
or
FCM Server Key
to send push notifications to signal the arrival of an incoming call. You need to use these values to create a
Push Credential
. If the
google-services.json
file used in your application is not the correct one associated with the
FCM SECRET
or
FCM Server Key
, notifications will fail.
identity
. Twilio will notify only most recent 10 registered devices, and the rest of the devices will not receive notifications.
The Programmable Voice SDK requires a new token format called the Twilio Access Token for authentication. Please update your token vending endpoint to generate Access Tokens
for your application.
Make sure the values for Account SID
, API signing key
, and secret
in the Access Token are all valid.
Yes. Push notifications for incoming calls are always sent with high priority. If the device has entered Doze mode, it should wake with the incoming notification delivery. See more about Doze mode and high-priority delivery here.
Note: This does not apply to version 2.1 or higher. The push notification sent to those versions will only be delivered if the device is reachable when the call is placed.
Twilio Voice SDKs use push notifications (APNS, FCM/GCM) as a mechanism to notify the callee of an incoming call. However, a problem presents itself when the callee's device is offline or not reachable: the push notification services cache the notification and re-attempt delivery at a much later time. The delayed notification may arrive after the call has already been terminated. The callee's device will briefly alert the user of a call that has already terminated, leading to a poor user experience.
Twilio plans to address this issue in a later release. In the meantime, the following is a proposal for a work around you can implement to avoid the poor user experience.
The following 4 step proposal allows an app developer to use time information as an additional criteria to determine whether or not to display a call notification to the user.
Generate a UTC based timestamp on the TwiML Application Server based on the Unix epoch in milliseconds.
var timeInMS = Date.now()
Add this generated timestamp to the <Dial>
used to reach the callee.
Parameters can be sent to a callee by initiating a TwiML <Dial>
verb. Use the <Parameter>
attribute to specify your key/value parameters as shown below. The value shown below is an example of a timestamp obtained in Step 1. You must pass the value as string.
1<?xml version="1.0" encoding="UTF-8"?>2<Response>3<Dial answerOnBridge="false" callerId="client:alice">4<Client>5<Identity>bob</Identity>6<Parameter name="timestamp" value="1555825985" />7</Client>8</Dial>9</Response>
When the call invite push message arrives to the callee, it will have the specified parameters.
Get the timestamp from the bundle or message provided by FCM when it arrives to the Android application. The method for doing this varies based on which version of the SDK you are using.
2.X SDKs
When receiving the push notification from Twilio, you can obtain the parameter from the bundle or message. The parameters are provided by FCM payload as the key: twi_params. The following shows how you can parse the contents of the data to get a map of the parameters you passed into the Dial. The "data" variable is the map provided by FCM.
1Map<String, String> customParameters = new HashMap<>();2String query_pairs = data.get(“twi_params”);3if (query_pairs != null) {4final String[] pairs = query_pairs.split("&");5for (String pair : pairs) {6final int idx = pair.indexOf("=");7final String key;8try {9key = idx > 0 ? pair.substring(0, idx) : pair;10final String value = idx > 0 && pair.length() > idx + 1 ? URLDecoder.decode(pair.substring(idx + 1).replaceAll("\\+", "%20"), "UTF-8") : null;11customParameters.put(key, value);12} catch (UnsupportedEncodingException e) {13e.printStackTrace();14}15}16}
3.X SDKs
When receiving the push notification from Twilio, you can obtain the parameter from CallInvite
with the following:
1Map<String, String> customParameters = callInvite.getCustomParameters();2String timestampString = customParameters.get(“timestamp”);
Compare the UTC based timestamp to the UTC time on the device and discard the notification if the device time is significantly later than the timestamp generated by the server.
Android
1// Get the timestamp from the customParameters map and the current device time2String timestampString = customParameters.get(“timestamp”);3long timestamp = Long.parseLong(timestampString);4long currentTimestamp = System.currentTimeMillis();56// Compare the time difference7if (currentTimestamp > timestamp + 60000) {8// discard notification...9} else {10// display notification...11}
We love feedback and questions, especially those with helpful debugging information so we can diagnose and respond in a timely manner. When submitting issues or support tickets, please add the following information:
DEBUG
:
Voice.setLogLevel(LogLevel.DEBUG)
When you have gathered all this helpful information, please file any issues you find on Github.
For general inquiries related to the Voice SDK you can file a support ticket.