Recognise returning visitors through the SDK

Pass your own user identifier when opening an agent and Handhold recognises the visitor when they come back, on any device or browser.

• Pick up where they left off. Returning visitors get their start screen prefilled and the agent remembers previous conversations, so nobody restarts from zero.
• Works across devices. Recognition no longer depends on the visitor's browser storage. The same identifier means the same visitor, whether they return on a laptop, a phone or a cleared browser.
• Signed on your server. Generate your signing secret under Settings → Visitor identity, compute HMAC-SHA256(secret, yourUserId) on your backend, and pass the digest as externalVisitorIdSignature alongside externalVisitorId. Only your server can vouch for who a visitor is, so nobody can claim someone else's history by guessing an identifier.

A session without a valid signature simply starts as a new anonymous visitor. The API reference has ready-to-copy snippets for Node, Python, Ruby and PHP.