--- "@context": https://schema.org "@type": TechArticle "@id": https://www.twilio.com/docs/voice/sip#article headline: SIP description: Connect your SIP infrastructure to Twilio for global reach and automation. Supports PSTN connectivity and outbound contact center use cases. url: https://www.twilio.com/docs/voice/sip inLanguage: en dateModified: 2026-08-24T17:18:11.000Z author: "@type": Organization name: Twilio Developer Education Team publisher: "@type": Organization name: Twilio --- # SIP Learn how Session Initiation Protocol (SIP) acts as a signaling protocol to manage user sessions over an IP network, allowing you to connect your existing communications infrastructure to Twilio. You can use this guide to create self-service automation, build inbound contact centers, manage outbound contact centers, and establish PSTN connectivity. See [Related reference documentation](#related-reference-documentation) to learn more about the SIP resources used in this guide. [All Programmable Voice SIP guides](/docs/voice/guides/by-feature-product#programmable-voice-sip) ### How Twilio uses SIP [Using SIP to connect to Twilio is one way](https://www.twilio.com/en-us/voice/sip-interface) to get access to Twilio's global reach and powerful automation and scripting functions. You can connect your on-site or virtual Private Branch Exchange (PBX) with Twilio's servers. Here's our overview of [connecting your existing SIP communications](/docs/voice/api/sending-sip) infrastructure to us. > \[!NOTE] > > For information about SIP Trunking with Twilio, check out our [Elastic SIP Trunking documentation](/docs/sip-trunking). Dig into our [API Reference docs for Twilio's SIP Domains](/docs/voice/sip/api): * [SIP Credential Resource](/docs/voice/sip/api/sip-credential-resource) * [SIP CredentialList](/docs/voice/sip/api/sip-credentiallist-resource)[Resource](/docs/voice/sip/api/sip-credentiallist-resource) * [SIP CredentialListMapping](/docs/voice/sip/api/sip-credentiallistmapping-resource)[Resource](/docs/voice/sip/api/sip-credentiallistmapping-resource) * [SIP Domain](/docs/voice/sip/api/sip-domain-resource)[Resource](/docs/voice/sip/api/sip-domain-resource) * [SIP IpAccessControlList Resource](/docs/voice/sip/api/sip-ipaccesscontrollist-resource) * [SIP IpAccessControlListMapping Resource](/docs/voice/sip/api/sip-ipaccesscontrollistmapping-resource) * [SIP IpAddress Resource](/docs/voice/sip/api/sip-ipaddress-resource) ## Manage SIP Domains in Twilio Console You can create and configure SIP Domains, IP Access Control Lists, and Credential Lists in [Twilio Console](https://1console.twilio.com/go?to=/account/__account__/us1/voice/sip-domains/sip-domains) or in the [legacy Console](https://console.twilio.com/us1/develop/voice/manage/sip-domains). ### View registered SIP endpoints On a SIP Domain's details page, you can see all devices registered with the Domain. Each entry shows the contact address, user agent, registration source IP, and expiration time. Use this to confirm registrations succeeded and to troubleshoot clients that aren't reachable. ## Twilio Console In [Twilio Console](https://1console.twilio.com/go?to=/account/__account__/us1/voice/sip-domains/sip-domains), go to **Voice** > **SIP domains**, select your SIP Domain, and then open the **Registered endpoints** tab. ## Legacy Console In the [legacy Console](https://console.twilio.com/us1/develop/voice/manage/sip-domains), go to **Voice** > **Manage** > **SIP Domains**, select your SIP Domain, and then open the **Registered SIP Endpoints** section. Registrations are Region-specific — endpoints only appear in the Region where the SIP Domain is routed. See [Regional SIP Domains](/docs/global-infrastructure/regional-sip-domains) for more on Region routing. ### Enable Secure Media Secure Media enforces SRTP for media on calls to and from the SIP Domain. When Secure Media is enabled, Twilio rejects calls that don't negotiate SRTP. Make sure your SIP clients and SBCs are configured for SRTP before enabling this setting in production. ## Twilio Console 1. In [Twilio Console](https://1console.twilio.com/go?to=/account/__account__/us1/voice/sip-domains/sip-domains), go to **Voice** > **SIP domains** and select your SIP Domain. 2. On the **Secure media** card, select **Enable secure media**. ## Legacy Console 1. In the [legacy Console](https://console.twilio.com/us1/develop/voice/manage/sip-domains), go to **Voice** > **Manage** > **SIP Domains** and select your SIP Domain. 2. On the **Secure Media** card, select **Edit** and enable the setting. ### Re-route a SIP Domain to a different Region A SIP Domain can exist in multiple [Twilio Regions](/docs/global-infrastructure/understanding-twilio-regions) but is only active in one Region at a time. ## Twilio Console 1. In [Twilio Console](https://1console.twilio.com/go?to=/account/__account__/us1/voice/sip-domains/sip-domains), go to **Voice** > **SIP domains** and select your SIP Domain. The **Active region** section shows which Region is active. 2. To change the active Region, select **Change active region**, select the target Region, and then select **Update region**. ## Legacy Console On the Domain's details page in the target Region in the [legacy Console](https://console.twilio.com/us1/develop/voice/manage/sip-domains), select **Re-route** on the routing card to make that Region active. See [Regional SIP Domains](/docs/global-infrastructure/regional-sip-domains) for details. ## Use cases for SIP with Twilio Programmable Voice This guide covers a feature that can support the following use cases: ### Create self-service automation You can use the interaction between SIP and TwiML to automate outbound calls that gather user input from your SIP endpoint. For example, you can use the `` verb to collect DTMF tones from a caller and route them through your PBX. To learn more advanced features that you can use with self-service automation, see [Voice self-service automation](/docs/voice/guides/self-service-automation). ### Create an inbound contact center By connecting your SIP infrastructure, you can route incoming calls from the PSTN through Twilio directly to your existing contact center equipment or softphones. To learn more advanced features that you can use with inbound contact centers, see [Voice inbound contact center](/docs/voice/guides/inbound-call-center). ### Create an outbound contact center You can use SIP to allow your agents to place outbound calls through Twilio's global network while maintaining your current call control environment. To learn more advanced features that you can use with outbound contact centers, see [Voice outbound contact center](/docs/voice/guides/outbound-call-center). ### Establish PSTN connectivity You can use SIP to bridge your private IP network with the public switched telephone network, enabling global reach for your existing SIP-based communications. To learn more advanced features that you can use with PSTN connectivity, see [Voice PSTN connectivity](/docs/voice/guides/pstn-connectivity). ## Next steps Explore the following guides to build on what you've learned in this guide: * [How to add programmability to your existing SIP network](/docs/voice/tutorials/how-to-add-programmability-to-your-existing-sip-network): Add Twilio's powerful scripting capabilities to your current infrastructure. * [How to route calls to your SIP network with an outbound call](/docs/voice/tutorials/how-to-route-calls-to-your-sip-network): Direct traffic from Twilio to your SIP endpoints. * [Making SIP calls](/docs/voice/api/sip-making-calls): Start placing calls using the SIP interface. ## Related reference documentation Find reference documentation for the topics on this page. * [SIP API](/docs/voice/sip/api) * [SIP Credential resource](/docs/voice/sip/api/sip-credential-resource) * [SIP CredentialList resource](/docs/voice/sip/api/sip-credentiallist-resource) * [SIP CredentialListMapping resource](/docs/voice/sip/api/sip-credentiallistmapping-resource) * [SIP Domain resource](/docs/voice/sip/api/sip-domain-resource) * [SIP IpAccessControlList resource](/docs/voice/sip/api/sip-ipaccesscontrollist-resource) * [SIP IpAccessControlListMapping resource](/docs/voice/sip/api/sip-ipaccesscontrollistmapping-resource) * [SIP IpAddress resource](/docs/voice/sip/api/sip-ipaddress-resource)