Multi-tenant chat software must treat tenant isolation as an authorization requirement on every query and API request. Hiding another customer link in the interface is not enough; the server must scope records by the authenticated organization. Use secure cookies, CSRF protection, prepared database statements, rate limiting, output escaping, private file storage, MIME validation and permission checks. Sensitive credentials should be encrypted at rest and never displayed again after saving. For embedded widgets, validate allowed domains and issue short-lived server tokens. For billing, never trust a browser success page; fulfilment should follow a verified signed server callback with duplicate-event protection.
Put these ideas into practice.
Create a workspace and test live chat on your own website.