GPT-5.1 Codex mini vs Qwen3.5 27B vs Seed 2.0 Code
Too close to call on our weighted score (Qwen3.5 27B 61, GPT-5.1 Codex mini 59, Seed 2.0 Code 57). The right pick depends on what you value most.
OpenAIGPT-5.1 Codex mini
59/100- ECI—
- Price$0.25 / $2.00
- Context400K
Alibaba (Qwen)Qwen3.5 27B
61/100- ECI—
- Price$0.30 / $2.40
- Context262K
ByteDance SeedSeed 2.0 Code
57/100- ECI—
- Price$0.475 / $2.37
- Context262K
Too close to call
It is close. Our weighted score puts them within 3 points (Qwen3.5 27B 61/100, GPT-5.1 Codex mini 59/100, Seed 2.0 Code 57/100), so choose by what matters most for your work: GPT-5.1 Codex mini on price and GPT-5.1 Codex mini for long inputs. 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 priceGPT-5.1 Codex miniGPT-5.1 Codex mini $0.688 · Qwen3.5 27B $0.825 · Seed 2.0 Code $0.95 per 1M tokens (3:1 blend)
- Longest contextGPT-5.1 Codex miniGPT-5.1 Codex mini 400,000 · Qwen3.5 27B 262,144 · Seed 2.0 Code 262,144 tokens
- Widest inputsQwen3.5 27BGPT-5.1 Codex mini: Text, Images · Qwen3.5 27B: Text, Images, Audio, Video · Seed 2.0 Code: Text, Images, Video
- Self-hostingQwen3.5 27BPublishes downloadable weights
| Measure | Weight | GPT-5.1 Codex mini | Qwen3.5 27B | Seed 2.0 Code |
|---|---|---|---|---|
| Price | 50% | 58 | 54 | 51 |
| Inputs & features | 30% | 70 | 90 | 80 |
| Context window | 20% | 44 | 37 | 37 |
| Overall | 100% | 59/100 | 61/100 | 57/100 |
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 | GPT-5.1 Codex miniOpenAI | Qwen3.5 27BAlibaba (Qwen) | Seed 2.0 CodeByteDance Seed |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.25 (best) | $0.30 | $0.475 |
| Output | $2.00 (best) | $2.40 | $2.37 |
| Cached input | — | — | $0.095 |
| Blended (3:1) | $0.688 (best) | $0.825 | $0.95 |
| Long-context rate | Same rate | Same rate | Over 32K: $0.712 / $3.56 |
| Price source | Median of 10 providers | Official Alibaba API | Official Volcengine Ark API |
| Limits | |||
| Context window | 400,000 tokens (best) | 262,144 tokens | 262,144 tokens |
| Max output | 128,000 tokens | 65,536 tokens | 131,072 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | No | No | No |
| Audio | No | Yes | No |
| Video | No | Yes | Yes |
| Reasoning | Yes | Yes | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | — | qwen3.5-27b | doubao-seed-2-0-code-preview-260215 |
| API providers | 10 | 16 (best) | 10 |
| Released | Nov 13, 2025 | Feb 23, 2026 | Feb 14, 2026 |
| 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.
- GPT-5.1 Codex mini$6.50
- Qwen3.5 27B$7.80
- Seed 2.0 Code$9.50
Which should you choose?
Which is better: GPT-5.1 Codex mini, Qwen3.5 27B or Seed 2.0 Code?
It is close. Our weighted score puts them within 3 points (Qwen3.5 27B 61/100, GPT-5.1 Codex mini 59/100, Seed 2.0 Code 57/100), so choose by what matters most for your work: GPT-5.1 Codex mini on price and GPT-5.1 Codex mini for long inputs. 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, GPT-5.1 Codex mini, Qwen3.5 27B or Seed 2.0 Code?
GPT-5.1 Codex mini is cheaper at $0.25 input / $2.00 output per million tokens (median across 10 API providers). Qwen3.5 27B costs $0.30 input / $2.40 output per million tokens (official Alibaba API price); Seed 2.0 Code costs $0.475 input / $2.37 output per million tokens (official Volcengine Ark API price). At a typical mix of three input tokens to one output token, that is $0.688 per million tokens for GPT-5.1 Codex mini versus $0.825 for Qwen3.5 27B (1.2× as much) and $0.95 for Seed 2.0 Code (1.4× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. GPT-5.1 Codex mini has not been scored yet, Qwen3.5 27B has not been scored yet and Seed 2.0 Code has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.1 Codex mini, Qwen3.5 27B and Seed 2.0 Code yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three 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 262,144 for Qwen3.5 27B and 262,144 for Seed 2.0 Code. Maximum output per response: GPT-5.1 Codex mini up to 128,000, Qwen3.5 27B up to 65,536, Seed 2.0 Code up to 131,072 tokens.
Which can read images, PDFs, audio or video?
GPT-5.1 Codex mini accepts text and images; Qwen3.5 27B accepts text, images, audio and video; Seed 2.0 Code accepts text, images and video. Qwen3.5 27B handles the widest range of inputs.
Are any of these open source?
Qwen3.5 27B publishes its weights and can be self-hosted; GPT-5.1 Codex mini and Seed 2.0 Code is proprietary.
Which is newer?
Qwen3.5 27B is the newest, released Feb 23, 2026. Seed 2.0 Code came out Feb 14, 2026; GPT-5.1 Codex mini came out Nov 13, 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 Oct 4, 2026.
