xAI—xAI released Grok-1 base model weights under Apache 2.0 license in rare frontier-model open release

On March 17, 2024 xAI released the 314-billion-parameter base weights of Grok-1 under the Apache 2.0 license, including the model architecture and tokenizer but not the fine-tuning or chat post-training data. At release Grok-1 was the largest fully open-weight model with permissive commercial-use rights. Critics noted the release excluded the instruction-tuned variant used in production and lacked accompanying training-data documentation. The release nonetheless represented a meaningful contribution to open AI research at a time when OpenAI, Anthropic and Google were systematically tightening release policies.