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 SpaceXAI: Grok 4.5
SpaceXAI: Grok 4.5 wins on 2 of 6 axes — pricing and capability skew in its favour for most workloads.
Grok 4.5 is SpaceXAI's smartest model with frontier performance on coding, knowledge work, and STEM.
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.3-Codex | SpaceXAI: Grok 4.5 | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 400K | 500K | 🏆 SpaceXAI: Grok 4.5 |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $1.75 | $2.00 | 🏆 OpenAI: GPT-5.3-Codex |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $14.00 | $6.00 | 🏆 SpaceXAI: Grok 4.5 |
| 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 SpaceXAI: Grok 4.5?
SpaceXAI: Grok 4.5 wins on 2 of 6 axes — pricing and capability skew in its favour for most workloads.
What's the price difference between OpenAI: GPT-5.3-Codex and SpaceXAI: Grok 4.5?
Input: $1.75 vs $2.00 per 1M tokens. Output: $14.00 vs $6.00 per 1M tokens.
What context windows do OpenAI: GPT-5.3-Codex and SpaceXAI: Grok 4.5 support?
OpenAI: GPT-5.3-Codex supports up to 400K tokens. SpaceXAI: Grok 4.5 supports up to 500K tokens.
Do both OpenAI: GPT-5.3-Codex and SpaceXAI: Grok 4.5 support tool calling?
OpenAI: GPT-5.3-Codex: yes. SpaceXAI: Grok 4.5: yes.
Compare OpenAI: GPT-5.3-Codex with other models
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