Immutable daily rates for uids and UTC days (POST /v1/rates/daily). Days are UTC calendar dates (YYYY-MM-DD) in the past. Crypto history older than about a year is served at daily granularity from daily candles (source s8) back to the earliest day each asset has; an asset with no such history is out_of_range. Each item carries a status: ok = exact immutable rate; out_of_range = the day is before the archive start, after today UTC, before the first available day of a crypto asset, or before the asset was listed (final, do not retry); pending = transient upstream miss, retry after retry_after seconds; unsupported = unknown uid. Limits (assets, quotes, assets times days) are in get_meta. Edge cases: read resource ratehub://docs/behavior (behaviour notes).