Does the B2 S3 Compatible API support Pre-Signed URLs?

As outlined in the S3 Compatible API documentation, Pre-Signed URLs are supported. However, Pre-Signed URLs with a time-limit are not supported. 

If you'd like to enforce a time restriction on a Pre-Signed URL you can do so by setting an expiry time when creating the Application Key you will use to generate the Pre-Signed URL. This will ensure that the key and Pre-Signed URL generated with it both expire at the same time. For more on App Keys, please refer to our documentation here.