Fast version of Grok 4 with SOTA cost-efficiency and 2M-token context.
Z.ai's large-scale reasoning flagship for complex software engineering and long-horizon agent tasks.
No shared demos for these models yet.
No captured outputs for these models yet.
Both Grok 4 Fast and GLM 5.3 are capable AI models. The best choice depends on your specific use case: consider pricing, context window, speed, and which capabilities (vision, reasoning, audio) you need.
Grok 4 Fast has a larger context window: Grok 4 Fast supports 2M tokens vs GLM 5.3 at 1M tokens.
Grok 4 Fast supports vision/image input, but GLM 5.3 does not.
Key differences: only Grok 4 Fast supports vision input; only GLM 5.3 offers extended reasoning mode. Compare full specs on this page.
If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both Grok 4 Fast and GLM 5.3 for free on idapt.app to see which performs better for your specific needs.