Seed 2.1 Pro
Summary
Seed 2.1 Pro is a proprietary language model from ByteDance Seed, released on 23 Jun 2026. It accepts text, images and video and generates text, with a 256K-token context window and up to 256K output tokens per response.
Flagship ByteDance Seed 2.1 model for complex multimodal reasoning, coding, and agents
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | ByteDance Seed |
|---|---|
| Release date | 23 Jun 2026 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 256K (256,000 tokens) [models.dev] |
| Max output | 256K tokens [models.dev] |
| Input | Text, images and video [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
| Structured output | Yes [models.dev] |
Seed 2.1 Pro API pricing by provider
USD per million tokens. Sorted by input price.
We do not currently track a paid API listing for this model.
Frequently asked questions
What is the context window of Seed 2.1 Pro?
Seed 2.1 Pro has a context window of 256,000 tokens (256K) and can generate up to 256,000 tokens in a single response, according to models.dev.
Is Seed 2.1 Pro open source?
No. Seed 2.1 Pro is a proprietary model; ByteDance Seed has not released its weights.
When was Seed 2.1 Pro released?
ByteDance Seed released Seed 2.1 Pro on 23 Jun 2026, according to models.dev.
Change history
No changes detected since we started tracking this model. We re-check every source daily.