# @aws-sdk/signature-v4-multi-region

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See also https://github.com/aws/aws-sdk-js-v3/tree/main#functionality-requiring-aws-common-runtime-crt.

## Usage

This package contains optional dependency [`@aws-sdk/signature-v4-crt`](https://www.npmjs.com/package/@aws-sdk/signature-v4).
You need to install this package explicitly to sign an un-regional request using SigV4a algorithm. The package contains
Node.js native implementation which requires building at installation. The installed package MAY NOT work if the
instance building the package runs a different operating system than the instance running the application.

The `@aws-sdk/signature-v4-crt` is only supported in Node.js currently because it depends on a native dependency.

Please refer to [this issue](https://github.com/aws/aws-sdk-js-v3/issues/2822) for more information.

Note: You can also use a native JS (non-CRT) implementation of the SigV4A signer, instructions for which are here:
https://github.com/aws/aws-sdk-js-v3/tree/main#functionality-requiring-aws-common-runtime-crt

Please refer to the note regarding bundle size in the link above, before deciding to use the JS SigV4A signer (including in browsers).

## Description

This package provides a SigV4-compatible request signer that wraps a pure-JS SigV4 signer
([`@aws-sdk/signature-v4`](https://www.npmjs.com/package/@aws-sdk/signature-v4)) for regional requests, and attempts to
call a native implementation of SigV4a signer([`@aws-sdk/signature-v4-crt`](https://www.npmjs.com/package/@aws-sdk/signature-v4))
it the request is multi-region.

A multi-region request is identified by the `signingRegion` parameter. A request is multi-region if the `signingRegion`
parameter is set to `*`.