# `EXLA.Backend`
[🔗](https://github.com/elixir-nx/nx/blob/v0.11.0/exla/lib/exla/backend.ex#L1)

A Nx tensor backend for the data kept on the device.

You can directly transfer to this backend by calling
`Nx.backend_transfer/2` or `Nx.backend_copy/2`. It
allows the following options:

  * `:client` - the client to store the data on.
    Defaults to EXLA's default client.

  * `:device_id` - which device to store it on.

To get the data out of the device backend into a regular
tensor, call `Nx.backend_transfer/1` (with the device
tensor as the single argument).

Note that the `EXLA.Backend` is asynchronous: operations
on its tensors *may* return immediately, before the tensor
data is available. The backend will then block only when
trying to read the data or when passing it to another operation.

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*Consult [api-reference.md](api-reference.md) for complete listing*