Agent may make mistakes and shouldn't be used in production
Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning.
import { streamText } from 'ai'
const result = streamText({ model: 'xai/grok-4-fast-reasoning', prompt: 'Why is the sky blue?'})Try out Grok 4 Fast Reasoning by xAI. Usage is billed to your team at API rates. Free users get $5 of credits every 30 days, and you are considered a free user if you haven't made a payment.
| Model |
|---|
| 2M | 5.5s | 730tps | $2.00/M | $6.00/M | Read: $0.2/M Write: — | — | — |  | 03/11/2026 | ||||
| 2M | 0.4s | 70tps | $2.00/M | $6.00/M | Read: $0.2/M Write: — | — | — | | 03/11/2026 | ||||
| 2M | 0.7s | 76tps | $2.00/M | $6.00/M | Read: $0.2/M Write: — | — | — | | 03/11/2026 | ||||
| 2M | 7.4s | 938tps | $2.00/M | $6.00/M | Read: $0.2/M Write: — | — | — | | 03/09/2026 | ||||
| 2M | 0.6s | 69tps | $2.00/M | $6.00/M | Read: $0.2/M Write: — | — | — | | 03/09/2026 | ||||
| 2M | 1.6s | 62tps | $2.00/M | $6.00/M | Read: $0.2/M Write: — | — | — | | 03/09/2026 | ||||
| — | — | | 01/28/2026 | ||||||||||
| — | — | | 01/28/2026 | ||||||||||
$0.00/img$0.01/sec | — | — | | 01/28/2026 | |||||||||
| 2M | 0.4s | 136tps | $0.20/M | $0.50/M | Read: $0.05/M Write: — | — | — | | 09/19/2025 | ||||
| 256K | 1.6s | 132tps | $0.20/M | $1.50/M | Read:$0.02/M Write:— | — | — | | 08/28/2025 | ||||
| 256K | 3.1s | 91tps | $3.00/M | $15.00/M | Read: $0.75/M Write: — | — | — | | 07/09/2025 | ||||
| 2M | 0.4s | 101tps | $0.20/M | $0.50/M | Read: $0.05/M Write: — | — | — | | 07/09/2025 | ||||
| 2M | 5.2s | 192tps | $0.20/M | $0.50/M | Read: $0.05/M Write: — | — | — | | 07/09/2025 | ||||
| 131K | 0.6s | 74tps | $3.00/M | $15.00/M | Read:$0.75/M Write:— | — | — | | 02/17/2025 | ||||
| 131K | 0.4s | 59tps | $5.00/M | $25.00/M | Read:$1.25/M Write:— | — | — | | 02/17/2025 | ||||
| 131K | 0.3s | 112tps | $0.30/M | $0.50/M | Read:$0.07/M Write:— | — | — | | 02/17/2025 | ||||
| 131K | 0.3s | 108tps | $0.60/M | $4.00/M | — | — | | 02/17/2025 |