GPT-5.3-Codex vs Grok Code Fast 1
OpenAI GPT-5.3-Codex | SpaceXAI Grok Code Fast 1 | |
|---|---|---|
| Overview | ||
| Company | OpenAI | SpaceXAI |
| Release date | Feb 5 2026 | Aug 28 2025 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 24% | — |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 83% | — |
Community preference (code) Arena Elo (Code)Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | 1406 | — |
| Timeline | ||
| Release gap | Grok Code Fast 1 shipped 161 days before GPT-5.3-Codex | |
Which is better: GPT-5.3-Codex or Grok Code Fast 1?
GPT-5.3-Codex and Grok Code Fast 1 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok Code Fast 1 shipped 161 days before GPT-5.3-Codex, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — GPT-5.3-Codex and Grok Code Fast 1 don't publish scores on any of the same benchmarks.
Frequently asked questions
GPT-5.3-Codex was released by OpenAI on Feb 5 2026.
Grok Code Fast 1 was released by SpaceXAI on Aug 28 2025.
Other comparisons
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