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# Query Several Collections in One Request

* **One request for up to 10 collections**: `POST /v3/collections/batch-query` takes a list of `collections`, and each entry accepts every v3 Query parameter plus `collection`. A top-level `query` fills any entry that omits its own. Captain runs the entries at the same time, so the request takes about as long as its slowest entry. See [Query Several Collections](/guides/advanced-querying#query-several-collections).
* **One ranked list per collection**: `results[i]` answers `collections[i]`, with the full Query response for that collection. Lists are never merged, and scores from different collections are not comparable. See [Batch Query](/reference/v3/batch-query).
* **Failures stay in their own entry**: a problem found before any search, such as an unknown collection or a missing query, fails the whole request. Once searching starts, a failed entry reports its own `error` in its slot and the rest still return. Retry only the failed entries.