Important Chainer is under the maintenance phase. Read the blog.

Bridge the gap between algorithms and implementations of deep learning


Chainer supports CUDA computation. It only requires a few lines of code to leverage a GPU. It also runs on multiple GPUs with little effort.


Chainer supports various network architectures including feed-forward nets, convnets, recurrent nets and recursive nets. It also supports per-batch architectures.


Forward computation can include any control flow statements of Python without lacking the ability of backpropagation. It makes code intuitive and easy to debug.

Quick Start

Install Chainer:

pip install chainer

Run the MNIST example:

tar xzf v7.8.1.tar.gz
python chainer-7.8.1/examples/mnist/

Learn more from the official documentation.

Extension Libraries

A library that implements various state-of-the-art deep reinforcement algorithms.
A collection of tools to train and run neural networks for computer vision tasks.


Introduction to Chainer

Companies supporting Chainer