> For the complete documentation index, see [llms.txt](https://docs.tryterra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tryterra.co/faq/help-topics/data-api-sdk/authentication-users-and-connection-state/reference-id-uniqueness-per-user.md).

# Can I share one reference\_id across multiple users?

Sharing a single `reference_id` across multiple end users is **not supported**. `reference_id` is meant to be your **unique internal identifier for one end user**.

Re-auth matching uses `reference_id` plus provider to find which connection belongs to a reconnecting user. When two users share a `reference_id`, that matching is ambiguous, so `auth_success` and `user_reauth` webhooks can fail to dispatch inconsistently.

**Give every end user their own distinct `reference_id`.**