GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-a…
Model details →OpenAI: GPT-5.3-Codex vs xAI: Grok 4
OpenAI: GPT-5.3-Codex wins on 3 of 6 axes — pricing and capability skew in its favour for most workloads.
Grok 4 is xAI's latest reasoning model with a 256k context window. It supports parallel tool calling, structured outputs, and both image and text inputs. Note that reasoning is not exposed, reasoning cannot be disabled, and the reasoning ef…
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.3-Codex | xAI: Grok 4 | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 400K | 256K | 🏆 OpenAI: GPT-5.3-Codex |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $1.75 | $3.00 | 🏆 OpenAI: GPT-5.3-Codex |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $14.00 | $15.00 | 🏆 OpenAI: GPT-5.3-Codex |
| 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-5.3-Codex better than xAI: Grok 4?
OpenAI: GPT-5.3-Codex wins on 3 of 6 axes — pricing and capability skew in its favour for most workloads.
What's the price difference between OpenAI: GPT-5.3-Codex and xAI: Grok 4?
Input: $1.75 vs $3.00 per 1M tokens. Output: $14.00 vs $15.00 per 1M tokens.
What context windows do OpenAI: GPT-5.3-Codex and xAI: Grok 4 support?
OpenAI: GPT-5.3-Codex supports up to 400K tokens. xAI: Grok 4 supports up to 256K tokens.
Do both OpenAI: GPT-5.3-Codex and xAI: Grok 4 support tool calling?
OpenAI: GPT-5.3-Codex: yes. xAI: Grok 4: yes.