GPT-5.1-Codex-Mini is a smaller and faster version of GPT-5.1-Codex
Model details →OpenAI: GPT-5.1-Codex-Mini vs xAI: Grok Code Fast 1
OpenAI: GPT-5.1-Codex-Mini and xAI: Grok Code Fast 1 are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
Grok Code Fast 1 is a speedy and economical reasoning model that excels at agentic coding. With reasoning traces visible in the response, developers can steer Grok Code for high-quality work flows.
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.1-Codex-Mini | xAI: Grok Code Fast 1 | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 400K | 256K | 🏆 OpenAI: GPT-5.1-Codex-Mini |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $0.25 | $0.20 | 🏆 xAI: Grok Code Fast 1 |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $2.00 | $1.50 | 🏆 xAI: Grok Code Fast 1 |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | — | 🏆 OpenAI: GPT-5.1-Codex-Mini |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is OpenAI: GPT-5.1-Codex-Mini better than xAI: Grok Code Fast 1?
OpenAI: GPT-5.1-Codex-Mini and xAI: Grok Code Fast 1 are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
What's the price difference between OpenAI: GPT-5.1-Codex-Mini and xAI: Grok Code Fast 1?
Input: $0.25 vs $0.20 per 1M tokens. Output: $2.00 vs $1.50 per 1M tokens.
What context windows do OpenAI: GPT-5.1-Codex-Mini and xAI: Grok Code Fast 1 support?
OpenAI: GPT-5.1-Codex-Mini supports up to 400K tokens. xAI: Grok Code Fast 1 supports up to 256K tokens.
Do both OpenAI: GPT-5.1-Codex-Mini and xAI: Grok Code Fast 1 support tool calling?
OpenAI: GPT-5.1-Codex-Mini: yes. xAI: Grok Code Fast 1: yes.