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Twilio Voice SDK lets you select the specific Twilio data center used when your Call connects to Twilio. Network communication to and from Twilio will originate/terminate from the fixed, static IP address ranges listed below for each region. Refer to these ranges if you need to configure your local network to allow communication or apply Quality of Service routing rules to communication with Twilio.

Region information for Programmable Voice SDK

By default, Programmable Voice SDK will use Twilio's Global Low Latency routing capability to determine which data center is closest to your user, establishing a connection through Twilio's nearest point of presence. Global Low Latency uses latency-based DNS lookups to determine the nearest data center. You may want to override this in some cases, especially when your users are working from a fixed location and using a DNS server in another region.

Use any one of the following values as the region parameter when calling Voice.setRegion(). Leaving the value undefined will cause Twilio to default to its Global Low Latency routing, which cause the SDK to establish its connection to the Twilio region closest to the user.

Region ID Location Media Server IP Address Range CIDR notation
au1 Australia -
br1 Brazil -
ie1 Ireland -, -,
de1 Frankfurt -
jp1 Japan -
sg1 Singapore -
us1 US East Coast (Virginia) - , -,
gll Use Twilio's Global Low Latency routing to select the data center with the lowest-latency connection to your user. Any of the above Any of the above

If you have access to private Interconnect connections you will also be able to use one of the following values as the region parameter.

Region ID Location Signaling and Media Server IP Address Range CIDR notation Port Range
us1-ix US East Coast (Virginia) over Interconnect exchange in Virginia - 443 (Signaling), 10,000 - 20,000 (Media)
us2-ix US West Coast (Oregon) over Interconnect exchange in San Jose - 443 (Signaling), 10,000 - 20,000 (Media)
ie1-ix Ireland over Interconnect exchange in London - 443 (Signaling), 10,000 - 20,000 (Media)

Who will benefit from this?

Global Low Latency uses latency-based DNS lookups to determine the nearest data center. We introduced setting a region in Voice SDK because there can be cases where the DNS address used by the App using Programmable Voice SDK may not represent their correct region. For example, if you are using a device in UK and the VPN server it is connected to is based in USA. If we relied on latency-based DNS lookups, the region Twilio will choose is going to be "us1" where "ie1" would have been preferred. Setting region on the caller side will guarantee the least latency in this scenario.

Example usage

Force connections through Twilio Ireland:


Force connections through Twilio US East Coast region over your private Interconnect connection to that region:


Let Twilio choose the nearest region, skip setting the region.

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