What is the meaning of session id in simple memory

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Hey @Mohammad_Shahid Welcome to the n8n community

In n8n’s Simple Memory node, the Session ID is just the identifier that tells n8n which conversation’s memory to save or load.

Think of it like a chat session key that groups messages together so the node knows what context belongs to which conversation. If you set the Session ID to something unique per user (like a phone number, a user ID, or a UUID), Simple Memory will store and retrieve memory tied to that ID each time. If you leave it blank or don’t pass one, n8n can’t locate or isolate the memory for a specific session.

When using a chat trigger, n8n usually generates the session ID automatically. But when you don’t use the chat trigger (or you want custom IDs), you must define the Session ID yourself so Simple Memory knows which conversation to load or save.

So in simple terms:

  • Session ID = the chat’s unique key that links stored memory to specific conversation history.

  • If different users share the same Session ID, their memory will be mixed.

  • If you want separate memory per user, make sure each one has a unique Session ID.