AionLabs: Aion-2.0 vs ByteDance Seed: Seed-2.0-Mini

AionLabs: Aion-2.0 is a text model from AionLabs, released on 2026-02-23. ByteDance Seed: Seed-2.0-Mini is a text model from ByteDance Seed, released on 2026-02-26. Both are served through api14 under the text category, and both take text in and return text out, so at the level of basic shape they are the same kind of thing: a chat style model you send a prompt to and get a completion back.

The differences show up in context, modalities and parameters. Seed-2.0-Mini has the larger context window at 262144 tokens, while Aion-2.0 sits at 131072 tokens. Seed-2.0-Mini also accepts image and video input alongside text, whereas Aion-2.0 accepts text only. On the parameter side, both expose include_reasoning, reasoning, max_tokens, response_format, temperature, tool_choice, tools and top_p, so tool calling and reasoning controls are available on either. Seed-2.0-Mini adds frequency_penalty, reasoning_effort, stop and structured_outputs, and it is the only one of the two with structured outputs. Neither is listed as the sole option for tools or reasoning, so those are a tie.

For practical selection, reach for Seed-2.0-Mini when the job involves long inputs, since its context window is twice the size, or when the input is not plain text, because it is the only one that reads images and video. It is also the pick when you need structured outputs or want to tune frequency_penalty, stop sequences or reasoning_effort. Aion-2.0 remains a reasonable choice for straightforward text generation, chat and tool calling where the prompt fits comfortably inside 131072 tokens and you do not need the extra sampling controls or structured output enforcement. If your pipeline is text only and short to medium in length, either model can do the work, and the decision comes down to which provider's behaviour you prefer rather than a hard capability gap.

Calling either model through api14 works the same way, because the API is OpenAI compatible. You point your client at the api14 base URL, send your request to the chat completions endpoint with your api14 key, and set the model field. To use Aion-2.0, set the model id to "aion-labs/aion-2.0". To use Seed-2.0-Mini, set it to "bytedance-seed/seed-2.0-mini". Everything else in the request body, the messages array, the tools, the temperature and the rest, keeps the same shape, so switching between the two is a one line change. Parameters that one model does not list, such as structured_outputs on Aion-2.0, should be dropped when you switch to it.

There is one case where the smaller context model is still the better pick: if you want to keep your request payload simple and avoid parameters that only one side supports, Aion-2.0 gives you the core set of controls without the extras, and it is a fine fit for text only tool calling and reasoning workflows. Seed-2.0-Mini is the cheaper of the two on both input and output, so cost conscious workloads will usually lean its way, but if your task is plain text and you have already tuned prompts against Aion-2.0, there is no capability reason to move.