Seed 2.1 Turbo vs GPT-5.1 Codex mini vs Aion-3.0-Mini
Too close to call on our weighted score (Seed 2.1 Turbo 56, GPT-5.1 Codex mini 54, Aion-3.0-Mini 41). The right pick depends on what you value most.
ByteDance SeedSeed 2.1 Turbo
56/100- ECI—
- Price$0.445 / $2.23
- Context256K
OpenAIGPT-5.1 Codex mini
54/100- ECI—
- Price$0.25 / $2.00
- Context400K
Aion Labs
Aion-3.0-Mini
41/100- ECI—
- Price$0.70 / $1.40
- Context131K
Too close to call
It is close. Our weighted score puts them within 2 points (Seed 2.1 Turbo 56/100, GPT-5.1 Codex mini 54/100, Aion-3.0-Mini 41/100), 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 · Aion-3.0-Mini $0.875 · Seed 2.1 Turbo $0.891 per 1M tokens (3:1 blend)
- Longest contextGPT-5.1 Codex miniGPT-5.1 Codex mini 400,000 · Seed 2.1 Turbo 256,000 · Aion-3.0-Mini 131,072 tokens
- Widest inputsSeed 2.1 TurboSeed 2.1 Turbo: Text, Images, Video · GPT-5.1 Codex mini: Text, Images · Aion-3.0-Mini: Text
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Seed 2.1 Turbo | GPT-5.1 Codex mini | Aion-3.0-Mini |
|---|---|---|---|---|
| Price | 50% | 50 | 55 | 50 |
| Inputs & features | 30% | 80 | 60 | 35 |
| Context window | 20% | 36 | 44 | 25 |
| Overall | 100% | 56/100 | 54/100 | 41/100 |
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 | Seed 2.1 TurboByteDance Seed | GPT-5.1 Codex miniOpenAI | Aion-3.0-MiniAion Labs |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.445 | $0.25 (best) | $0.70 |
| Output | $2.23 | $2.00 | $1.40 (best) |
| Cached input | $0.089 | — | — |
| Blended (3:1) | $0.891 | $0.688 (best) | $0.875 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Volcengine Ark API | Median of 16 providers | Median of 4 providers |
| Limits | |||
| Context window | 256,000 tokens | 400,000 tokens (best) | 131,072 tokens |
| Max output | 256,000 tokens (best) | 128,000 tokens | 32,768 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | No |
| PDFs | No | No | No |
| Audio | No | No | No |
| Video | Yes | No | No |
| Reasoning | Yesminimal · low · medium · high · xhigh · max | Yes | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | No |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | doubao-seed-2-1-turbo-260628 | — | — |
| API providers | 8 | 16 (best) | 4 |
| Released | Jun 23, 2026 | Nov 13, 2025 | May 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.
- Seed 2.1 Turbo$8.91
- GPT-5.1 Codex mini$6.50
- Aion-3.0-Mini$9.80
Which should you choose?
Which is better: Seed 2.1 Turbo, GPT-5.1 Codex mini or Aion-3.0-Mini?
It is close. Our weighted score puts them within 2 points (Seed 2.1 Turbo 56/100, GPT-5.1 Codex mini 54/100, Aion-3.0-Mini 41/100), 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, Seed 2.1 Turbo, GPT-5.1 Codex mini or Aion-3.0-Mini?
GPT-5.1 Codex mini is cheaper at $0.25 input / $2.00 output per million tokens (median across 16 API providers). Aion-3.0-Mini costs $0.70 input / $1.40 output per million tokens (median across 4 API providers); Seed 2.1 Turbo costs $0.445 input / $2.23 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 $0.875 for Aion-3.0-Mini (1.3× as much) and $0.891 for Seed 2.1 Turbo (1.3× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Seed 2.1 Turbo has not been scored yet, GPT-5.1 Codex mini has not been scored yet and Aion-3.0-Mini has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Seed 2.1 Turbo, GPT-5.1 Codex mini and Aion-3.0-Mini 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 256,000 for Seed 2.1 Turbo and 131,072 for Aion-3.0-Mini. Maximum output per response: Seed 2.1 Turbo up to 256,000, GPT-5.1 Codex mini up to 128,000, Aion-3.0-Mini up to 32,768 tokens.
Which can read images, PDFs, audio or video?
Seed 2.1 Turbo accepts text, images and video; GPT-5.1 Codex mini accepts text and images; Aion-3.0-Mini accepts text. Seed 2.1 Turbo handles the widest range of inputs.
Are any of these open source?
No. Seed 2.1 Turbo, GPT-5.1 Codex mini and Aion-3.0-Mini are proprietary and only available through APIs and apps.
Which is newer?
Seed 2.1 Turbo is the newest, released Jun 23, 2026. Aion-3.0-Mini came out May 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 Nov 2, 2026.
