Sync accepted; convergence proceeds asynchronously per target.

Invalid request (code: invalid_request).

Missing, expired, or invalid bearer token (code: unauthorized). The response carries WWW-Authenticate: Bearer error="invalid_token". Re-authenticate to obtain a fresh token.

The token is valid but lacks the required scope (code: forbidden).

No such resource for your organization (code: not_found). Also returned when a resource exists but belongs to a different organization.

State conflict — no changes were applied. The code distinguishes the cause: version_mismatch (the version you sent is stale — re-fetch and retry) or precondition_failed (the action isn't valid for the invoice's current state, e.g. editing or deleting an already-issued invoice, issuing/deleting something that isn't a draft, sharing without a payment account, voiding a partially/fully paid invoice, or syncing a draft).

Too many requests (code: rate_limited). Wait for Retry-After seconds, then retry.

Unexpected server error (code: internal_error).