GPT-5 Nano vs Qwen3.5 9B vs Seed 2.0 Code

Qwen3.5 9B is the better all-round choice, scoring 79/100 against GPT-5 Nano (75) and Seed 2.0 Code (57). It leads on price. GPT-5 Nano wins on context window. 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.

Qwen3.5 9B is cheaper at $0.10 input / $0.15 output per million tokens (median across 14 API providers). GPT-5 Nano costs $0.05 input / $0.40 output per million tokens (official OpenAI 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 $0.113 per million tokens for Qwen3.5 9B versus $0.138 for GPT-5 Nano (1.2× as much) and $0.95 for Seed 2.0 Code (8.4× as much).

There is no independent benchmark that covers all three models yet. GPT-5 Nano has an ECI of 139.4, Qwen3.5 9B has an ECI of 139.5 and Seed 2.0 Code has not been scored yet.

There are no published SWE-bench Verified results for GPT-5 Nano, Qwen3.5 9B 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.

GPT-5 Nano has the largest context window at 400,000 tokens, against 262,144 for Qwen3.5 9B and 262,144 for Seed 2.0 Code. Maximum output per response: GPT-5 Nano up to 128,000, Qwen3.5 9B up to 65,536, Seed 2.0 Code up to 131,072 tokens.

GPT-5 Nano accepts text and images; Qwen3.5 9B accepts text, images and video; Seed 2.0 Code accepts text, images and video. Qwen3.5 9B handles the widest range of inputs.

Qwen3.5 9B publishes its weights and can be self-hosted; GPT-5 Nano and Seed 2.0 Code is proprietary.

Qwen3.5 9B is the newest, released Feb 23, 2026. Seed 2.0 Code came out Feb 14, 2026; GPT-5 Nano came out Aug 7, 2025. Knowledge cutoff: GPT-5 Nano May 30, 2024.

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.