Create Subaccount
Create a new trading subaccount. Any active org member can create one; account_type is pinned to non_custodial server-side. A non-admin creator gets an explicit admin grant on the new subaccount (org admins hold derived access on every subaccount and never get grant rows).
Runs on the unscoped session: the creator holds no user:manage grant on the subaccount until this transaction writes it, so the scoped-session RLS WITH CHECK on subaccount_grants can never admit the bootstrap row.
Authorizations
UUID of your API key (from Settings → API Keys).
Current unix seconds. Must be within 30s of server time.
Base64 Ed25519 signature over the canonical request: METHOD\nPATH\nSORTED_QUERY\nTIMESTAMP\nSHA256(body) hex. See /api-reference/authentication for the full recipe.
Body
Response
Successful Response
Schema for subaccount response.
Type of trading subaccount.
custodial, non_custodial 
