SIP URI
A SIP URI is an address that identifies a user, service, or endpoint for routing a SIP session over an IP network. It commonly takes a form such as sip:sales@example.com, combining the SIP scheme with a user or service name and a domain.
How a SIP URI works
The domain tells SIP infrastructure where to begin resolving the destination, while the user portion identifies the intended recipient within that domain. Depending on the deployment, that recipient might be a person, a desk phone, an IVR, a queue, a trunk destination, or an AI voice agent. A secure form can use the sips: scheme when the signaling route is required to use protected transport.
A URI can also include parameters that refine transport or routing behavior. Those details are part of the address, not a guarantee that the endpoint is registered, authorized, or reachable. SIP servers may apply location records, routing rules, authentication, and policy before the request reaches its final destination.
SIP URIs resemble email addresses, but they do not represent email accounts. They are identifiers for SIP signaling. They are also different from phone numbers: a phone number may be translated into a SIP URI by a carrier or PBX so that the call can continue across an IP network.
Why it matters for AI phone calls
SIP integrations often need explicit source and destination addresses. An inbound route may send a number to the URI associated with an agent, while an outbound or transfer action may target another URI. If the user, domain, scheme, or routing parameter is wrong, the call may fail before any audio is exchanged.
Teams should document whether each field expects a full SIP URI, a hostname, or a phone number. They should also test the URI from the network that will originate production traffic, since a syntactically correct address can still fail because of authentication, domain resolution, firewall policy, or an unavailable endpoint.
A URI should not be treated as a secret by itself. Credentials, tokens, and private network details used alongside it still need appropriate protection. Logs can retain the URI for routing diagnosis while access controls protect sensitive authentication material.