Grok Code Fast 1 vs GPT-5.1 Codex mini
GPT-5.1 Codex mini comes out ahead, 54 to 48 on our weighted score, though Grok Code Fast 1 is 24% cheaper per token.
xAIGrok Code Fast 1
48/100- ECI—
- Price$0.20 / $1.50
- Context256K
- Our pick
OpenAIGPT-5.1 Codex mini
54/100- ECI—
- Price$0.25 / $2.00
- Context400K
Add a model
Make it a three-way comparison.
GPT-5.1 Codex mini is our pick
GPT-5.1 Codex mini is the better all-round choice, scoring 54/100 against Grok Code Fast 1 (48). It leads on inputs & features and context window. Grok Code Fast 1 wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceGrok Code Fast 1Grok Code Fast 1 $0.525 · GPT-5.1 Codex mini $0.688 per 1M tokens (3:1 blend)
- Longest contextGPT-5.1 Codex miniGPT-5.1 Codex mini 400,000 · Grok Code Fast 1 256,000 tokens
- Widest inputsGPT-5.1 Codex miniGrok Code Fast 1: Text · GPT-5.1 Codex mini: Text, Images
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Grok Code Fast 1 | GPT-5.1 Codex mini |
|---|---|---|---|
| Price | 50% | 60 | 55 |
| Inputs & features | 30% | 35 | 60 |
| Context window | 20% | 36 | 44 |
| Overall | 100% | 48/100 | 54/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Grok Code Fast 1xAI | GPT-5.1 Codex miniOpenAI |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.20 (best) | $0.25 |
| Output | $1.50 (best) | $2.00 |
| Cached input | — | — |
| Blended (3:1) | $0.525 (best) | $0.688 |
| Long-context rate | Same rate | Same rate |
| Price source | Median of 5 providers | Median of 16 providers |
| Limits | ||
| Context window | 256,000 tokens | 400,000 tokens (best) |
| Max output | 10,000 tokens | 128,000 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | Yes |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| Structured output | No | No |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | — | — |
| API providers | 7 | 16 (best) |
| Released | Sep 2, 2025 | Nov 13, 2025 |
| Knowledge cutoff | — | Sep 30, 2024 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Grok Code Fast 1$5.00
- GPT-5.1 Codex mini$6.50
Which should you choose?
Which is better: Grok Code Fast 1 or GPT-5.1 Codex mini?
GPT-5.1 Codex mini is the better all-round choice, scoring 54/100 against Grok Code Fast 1 (48). It leads on inputs & features and context window. Grok Code Fast 1 wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Grok Code Fast 1 or GPT-5.1 Codex mini?
Grok Code Fast 1 is cheaper at $0.20 input / $1.50 output per million tokens (median across 5 API providers). GPT-5.1 Codex mini costs $0.25 input / $2.00 output per million tokens (median across 16 API providers). At a typical mix of three input tokens to one output token, that is $0.525 per million tokens for Grok Code Fast 1 versus $0.688 for GPT-5.1 Codex mini (1.3× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Grok Code Fast 1 has not been scored yet and GPT-5.1 Codex mini has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Grok Code Fast 1 and GPT-5.1 Codex mini yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
GPT-5.1 Codex mini has the largest context window at 400,000 tokens, against 256,000 for Grok Code Fast 1. Maximum output per response: Grok Code Fast 1 up to 10,000, GPT-5.1 Codex mini up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Grok Code Fast 1 accepts text; GPT-5.1 Codex mini accepts text and images. GPT-5.1 Codex mini handles the widest range of inputs.
Are any of these open source?
No. Grok Code Fast 1 and GPT-5.1 Codex mini are proprietary and only available through APIs and apps.
Which is newer?
GPT-5.1 Codex mini is the newest, released Nov 13, 2025. Grok Code Fast 1 came out Sep 2, 2025. Knowledge cutoff: GPT-5.1 Codex mini Sep 30, 2024.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
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