Comparison
GPT-5.1 vs Grok 4.3
How GPT-5.1 and Grok 4.3 compare on the numbers that decide the call - and how to switch between them without touching your code.
| Spec | GPT-5.1 | Grok 4.3 |
|---|---|---|
| Input price / 1Mlower is cheaper | $1.25 | $1.25 |
| Output price / 1Mlower is cheaper | $10 | $2.5 |
| Context windowbigger fits more | 400K | 1M |
| Typical speedfaster median | 1.4s | 2.8s |
| Quality score | 95/100 | 91/100 |
| Provider | OpenAI | xAI |
Which should you pick?
- Grok 4.3 takes a larger context window (1M tokens).
- GPT-5.1 is usually the faster to answer.
- GPT-5.1 scores higher on the composite quality benchmark.
You do not have to choose permanently. Name one as your first choice and let Final Router fall back to the other when a provider fails - the request still gets answered, and the log shows which model replied.
Common questions
- Is GPT-5.1 or Grok 4.3 cheaper?
- Their input token prices are the same ($1.25 per 1M). Compare output: $10 vs $2.5.
- Can I switch between GPT-5.1 and Grok 4.3 without changing my code?
- Yes. Both are called through the same OpenAI-compatible endpoint - change only the model id ("openai/gpt-5.1" or "xai/grok-4.3"), or let a routing policy fall back from one to the other automatically.