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

AionLabs: Aion-2.0 is a text model from AionLabs, released on 2026-02-23. ByteDance Seed: Seed-2.0-Code is a text model from ByteDance Seed, released on 2026-08-12. Both are served on api14 as chat models with text output, and both accept tool definitions, so the choice between them comes down to context size, input types, parameter surface and price rather than to one being a general assistant and the other something else entirely.

The clearest split is context and input modality. Seed-2.0-Code carries a context window of 262144 tokens, twice the 131072 tokens of Aion-2.0, and it accepts images and video alongside text, while Aion-2.0 accepts text only. Seed-2.0-Code also exposes more request parameters: frequency_penalty, reasoning_effort, stop and structured_outputs on top of the shared set, whereas Aion-2.0 supports include_reasoning, max_tokens, reasoning, response_format, temperature, tool_choice, tools and top_p. Both can emit reasoning, so that is not a differentiator. Structured outputs are listed only for Seed-2.0-Code. On price, Seed-2.0-Code is the cheaper of the two for input, while Aion-2.0 is the cheaper for output, so the cost balance shifts with how much you send versus how much you generate.

For practical work, reach for Seed-2.0-Code when the job involves long inputs, large repositories, multi-file context, screenshots, diagrams or video frames, or when you need structured outputs and fine control over reasoning effort and stopping behaviour. Its larger window and multimodal input make it the natural fit for code oriented and inspection heavy tasks. Reach for Aion-2.0 when your prompts and completions are text only, when you want a smaller, simpler parameter surface, and when output volume dominates your bill, since it is the cheaper side for output tokens. If your workload is mostly short text prompts with long generated answers, Aion-2.0 is the more economical default; if it is mostly long inputs with short answers, Seed-2.0-Code is.

Calling either model through api14 works the same way because the gateway is OpenAI compatible. You point your client at the api14 base URL, send a standard chat completions request with your messages and any tools or response_format you need, and authenticate with your api14 key. The only change between the two is the model id string: use "aion-labs/aion-2.0" for AionLabs and "bytedance-seed/seed-2.0-code" for ByteDance Seed. Everything else in your request body and your parsing code stays identical, so you can switch models per request, run both side by side, or route by task without maintaining two integrations.

There are still cases where the other model wins. If you have settled on Seed-2.0-Code for its context and multimodal input but your workload generates very long outputs, Aion-2.0 remains the better pick on output price, and its text only scope is enough for pure text generation. Conversely, if you are using Aion-2.0 but a request needs image or video input, a context beyond 131072 tokens, or structured outputs, Seed-2.0-Code is the one that can serve it. Check the live price table on this page for current rates before you commit, since the cheaper side depends on your input to output ratio.