Seed 1.8
Summary
Seed 1.8 is a proprietary language model from ByteDance Seed, released on 1 Sept 2025. It accepts text and images and generates text, with a 256K-token context window and up to 33K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $0.25 per million input tokens and $2 per million output tokens (Vercel AI Gateway), across 1 provider we track.
Multimodal reasoning model for visual analysis, planning, and tool use
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | ByteDance Seed |
|---|---|
| Release date | 1 Sept 2025 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 256K (256,000 tokens) [models.dev] |
| Max output | 33K tokens [models.dev] |
| Knowledge cutoff | Oct 2024 [models.dev] |
| Input | Text and images [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
Seed 1.8 API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| Vercel AI Gateway bytedance/seed-1.8 | $0.25 | $2 | $0.05 | 256K | models.dev, 4 Oct 2026 |
Frequently asked questions
What is the context window of Seed 1.8?
Seed 1.8 has a context window of 256,000 tokens (256K) and can generate up to 32,768 tokens in a single response, according to models.dev.
How much does the Seed 1.8 API cost?
Seed 1.8 is listed from $0.25 per million input tokens and $2 per million output tokens (Vercel AI Gateway). Prices last verified 4 Oct 2026.
Is Seed 1.8 open source?
No. Seed 1.8 is a proprietary model; ByteDance Seed has not released its weights. It is available through APIs including Vercel AI Gateway.
When was Seed 1.8 released?
ByteDance Seed released Seed 1.8 on 1 Sept 2025, according to models.dev.
Change history
No changes detected since we started tracking this model. We re-check every source daily.