On November 11, Runway announced that Praxis-1, its world action model, is now available to everyone with open weights under the Apache 2.0 license. Any robotics developer or researcher can download, deploy, and commercially use the 27-billion-parameter model without waiting for an invitation or a license. Praxis-1 was introduced in September with a promise to go open; that promise has now been kept.
Praxis-1 is a 27B-parameter mixture-of-experts diffusion transformer that predicts video and actions together. On Nvidia's RoboLab-120 leaderboard it tops the ranking with a 46.2% success rate, ahead of FLUX 3 Action at 42.9%, Cosmos3 Nano at 36.8%, and π0.5 at 28.0%. The model is live on GitHub and Hugging Face with native LeRobot support, also ships in vLLM-Omni, and hosted inference is offered through Reactor. Weights, inference, and fine-tuning code are all released under Apache 2.0, including for commercial use, with support for full fine-tuning and LoRA. It runs on data-center GPUs such as the H100 and B200, workstation cards such as the RTX 5090 and RTX PRO 6000, and Jetson Thor on the robot itself.
A new robot does not mean training from scratch
Praxis-1 learns how objects behave and how tasks unfold from large-scale video pretraining, so moving to new hardware takes only light fine-tuning. Runway's three launch partners have already run it on their own machines: a legged humanoid from Noble Machines, a six-axis industrial arm from Standard Bots, and a dual-arm warehouse robot from Ultra. Fine-tuned on Google's RT-1 robot, which never appeared in its training data, Praxis-1 reaches 80.0% success on SimplerEnv, far above the original RT-1 policy at 52.4%.
For robotics developers, the value of Praxis-1 is not the leaderboard number but the fact that it puts a complete "world model plus action" stack in everyone's hands: commonsense learned from video transfers to new embodiments, and even a small team can fine-tune a working policy on its own hardware. Runway is also a founding member of the Cosmos Coalition, and this release is part of that alliance's push for open world models. The next thing to watch is how many kinds of real robots the community puts Praxis-1 into, and how it performs outside the warehouse.
