Models / xAI
Grok 4.1 Fast
Grok 4.1 Fast has two API variants with the same 2M-token catalog context: reasoning for multi-step tasks, and non-reasoning for direct replies. Compare both IDs here rather than treating them as separate model families.
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| API model ID | Context | Vision | Reasoning | Native search |
|---|---|---|---|---|
grok-4-1-fast-reasoning | 2M tokens | Supported | Effort levels | Not enabled |
grok-4-1-fast-non-reasoning | 2M tokens | Supported | Off | Not enabled |
Source: the app's bundled model catalog, reviewed October 27, 2026. This is a configuration snapshot, not a live provider availability or quality test. Context is shared by instructions, history, attachments, and the reply.
A task to test before choosing Grok 4.1 Fast
Send one constraint-solving prompt and one short rewrite to both Fast API IDs, with the same input and output limits.
Acceptance check: Compare constraint violations, time to first token, and billed tokens. Keep reasoning only where it earns its extra work.
Watch out: Both variants have the same 2M context in the catalog. The reasoning flag differs; native search is not enabled for either here.
Suggested evaluation protocol; we are not reporting benchmark results.
Best for
Reasoning tasks where speed matters
Other xAI models
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