GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic workflows spanning software e…
Model details →OpenAI: GPT-5.1-Codex-Max vs xAI: Grok 4.20 Beta
xAI: Grok 4.20 Beta wins on 2 of 6 axes — pricing and capability skew in its favour for most workloads.
Grok 4.20 Beta is xAI's newest flagship model with industry-leading speed and agentic tool calling capabilities. It combines the lowest hallucination rate on the market with strict prompt adherance, delivering consistently precise and truth…
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.1-Codex-Max | xAI: Grok 4.20 Beta | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 400K | 2M | 🏆 xAI: Grok 4.20 Beta |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $1.25 | $2.00 | 🏆 OpenAI: GPT-5.1-Codex-Max |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $10.00 | $6.00 | 🏆 xAI: Grok 4.20 Beta |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | Yes | Tie |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is OpenAI: GPT-5.1-Codex-Max better than xAI: Grok 4.20 Beta?
xAI: Grok 4.20 Beta wins on 2 of 6 axes — pricing and capability skew in its favour for most workloads.
What's the price difference between OpenAI: GPT-5.1-Codex-Max and xAI: Grok 4.20 Beta?
Input: $1.25 vs $2.00 per 1M tokens. Output: $10.00 vs $6.00 per 1M tokens.
What context windows do OpenAI: GPT-5.1-Codex-Max and xAI: Grok 4.20 Beta support?
OpenAI: GPT-5.1-Codex-Max supports up to 400K tokens. xAI: Grok 4.20 Beta supports up to 2M tokens.
Do both OpenAI: GPT-5.1-Codex-Max and xAI: Grok 4.20 Beta support tool calling?
OpenAI: GPT-5.1-Codex-Max: yes. xAI: Grok 4.20 Beta: yes.