xAI
grok-4-fast-reasoning
Fast Grok model for responsive chat, reasoning, and tool-assisted work
Model facts
- Context window
- 2M tokens
- Maximum output
- 2M tokens
- Cheapest paid input
- $0.18 per 1M tokens
- Cheapest paid output
- $0.45 per 1M tokens
- Open weights
- no
- Providers
- 4
Capabilities and modalities
reasoning, tool calling, structured output, attachments, temperature control, text, image.
Observed price history
- 2026-08-24: $0.18 input / $0.45 output per 1M tokens
API providers
- Jiekou.AI — model id grok-4-fast-reasoning; $0.18 input / $0.45 output per 1M tokens; provider documentation
- 302.AI — model id grok-4-fast-reasoning; $0.2 input / $0.5 output per 1M tokens; provider documentation
- Helicone — model id grok-4-fast-reasoning; $0.2 input / $0.5 output per 1M tokens; provider documentation
- Poe — model id xai/grok-4-fast-reasoning; $0.2 input / $0.5 output per 1M tokens; provider documentation