Grok vs. Jurassic

Grok

Grok is the proprietary model family available through xAI's products and API. Grok 4.5 is the current generation, focused on coding, agentic tasks, reasoning, and knowledge work.

xAI introduced Grok in November 2023 and released the weights for Grok-1 under Apache 2.0 in March 2024. Later generations are proprietary and available through Grok, X, and the xAI API. Grok 4.5, released in July 2026, is xAI's current flagship model for software engineering, tool-driven agents, complex reasoning, and professional knowledge work.

Further reading

• github.com/xai-org/grok-1/tree/main
• x.ai/news/grok-4-5

Jurassic

Developed by AI21, a startup founded by luminaries from Stanford and Mobileye, Jurassic was one of the first LLMs to challenge GPT-3. While it includes some support for code, Jurassic is more focused on reading and writing use cases, perhaps linked to AI21's development of other tools such as Wordtune. Jurassic also introduced the MRKL system for interfacing with external, non-neural modules.

Further reading

• www.ai21.com/blog/jurassic-x-crossing-the-neuro-symbolic-chasm-with-the-mrkl-system