TensorFlow also has a Swift API in development [3]. The people at FastAI seem quite excited about it [4].
[1] https://developer.ibm.com/swift/
[2] https://github.com/IBM-Swift/Kitura
[3] https://www.tensorflow.org/swift/api_docs
[4] https://www.fast.ai/2019/03/06/fastai-swift/