A group of researchers has made available an open implementation of the Dreamer 4 world-model pipeline, which is a complex AI model used for tasks such as video processing. The implementation, called Open Dreamer, is written in JAX and Flax NNX and includes the full training recipe. The model's components include a causal video tokenizer, an action-conditioned latent dynamics model, and a rollout generator. This release provides a framework for others to build upon and potentially improve the model. The development of such models has significant implications for artificial intelligence research and its potential applications.