signalingState

SignalingState is a property of the WebRTC RTCPeerConnection interface that describes the current state of the signaling process used to negotiate a session description protocol (SDP) exchange between peers. It reflects where in the offer/answer negotiation the connection currently stands and changes in response to creating offers and answers, applying remote descriptions, or closing the connection. The typical values are stable, have-local-offer, have-remote-offer, have-local-pranswer, have-remote-pranswer, and closed.

Each value signals a specific phase of negotiation: stable indicates no ongoing offer/answer exchange. have-local-offer means the local party has created an offer and is awaiting a remote description. have-remote-offer indicates a remote party has sent an offer and the local party should respond with an answer. have-local-pranswer and have-remote-pranswer denote provisional answers (pranswer) have been created or received as part of certain negotiation patterns. closed signifies that the RTCPeerConnection has been closed and signaling is finished.

SignalingState is a read-only property that updates automatically as the signaling flow progresses. It is influenced by operations such as createOffer, createAnswer, setLocalDescription, setRemoteDescription, and close. It does not reflect ICE connectivity status or actual media transmission; rather, it tracks the negotiation lifecycle. Developers commonly listen for the onsignalingstatechange event to adapt UI and logic to the current negotiation phase, ensuring that offers and answers are created and applied in the correct order. In typical usage, transitions move from stable to have-local-offer or have-remote-offer during negotiation and return to stable after successful description exchanges, with pranswer states used for certain intermediate patterns.