Start an attachment (member token)
The member-token twin of Start a card attachment: same rows, same hosted page, authenticated as the member instead of naming them with user_id. In sandbox this seeds an instantly-active test enrollment so the full flow is rehearsable without a browser.
user_id.
In sandbox this seeds an instantly-active test enrollment, so an agent can
rehearse the whole add-then-create flow with no browser step.Authorizations
The user's connection access_token (user authentication), or an org-minted buy_token for org-owned accounts.
Response
A card is already attached.
card_attachment The attachment id.
pending — the user has not finished the attach link. active — attached; create_card now mints against this card. ineligible — this card cannot be attached; fall back to wallet funding + create_card.
pending, active, ineligible The hosted link the user opens to add their card. Present only on the start response.
When the attach link expires (48 hours). Present only on the start response.
Display details of the attached card. Present when status is active.
Why the card cannot be attached (e.g. issuer_excluded, commercial_card). Present when status is ineligible.
Human-readable guidance. Present when status is ineligible.

