[Home](./index.md) > [puppeteer](./puppeteer.md) > [Protocol](./puppeteer.protocol.md) > [Target](./puppeteer.protocol.target.md) > [SendMessageToTargetRequest](./puppeteer.protocol.target.sendmessagetotargetrequest.md) > [sessionId](./puppeteer.protocol.target.sendmessagetotargetrequest.sessionid.md) ## Protocol.Target.SendMessageToTargetRequest.sessionId property Identifier of the session. Signature: ```typescript sessionId?: SessionID; ```