ByteDance Seed · Released Dec 28, 2025Seed 1.8
ByteDance Seed model for multimodal reasoning, long-context analysis, and agent workflows.
- Capability
- —No ECI score yet
- Input
- $0.119per 1M tokens
- Output
- $1.19per 1M tokens
- Context
- 256K64K max output
What it costs
- Input
- $0.119per million tokens
- Output
- $1.19per million tokens
- Cached input
- $0.024per million tokens
- Over 32K tokens
- $0.178 / $2.37input / output per million
- Blended (3:1)
- $0.386cheaper than 67% of priced models
Typical monthly bills
| Monthly usage | Estimated cost |
|---|---|
| Side project2M input + 0.5M output tokens | $0.831 |
| Team assistant25M input + 5M output tokens | $8.91 |
| Production app250M input + 50M output tokens | $89.06 |
Official Volcengine Ark API price, as listed on models.dev.
Independent benchmarks
Epoch AI has not published a Capabilities Index score for Seed 1.8 yet.
The details
- Lab
- ByteDance Seed
- Released
- Dec 28, 2025
- Context window
- 256,000 tokens
- Max output
- 64,000 tokens
- Inputs
- Text, Images
- Output
- Text
- Reasoning
- Adjustable effort minimal · low · medium · high · xhigh · max
- Tool calling
- Yes
- Structured output
- Yes
- Weights
- Proprietary
- API model ID
doubao-seed-1-8-251228on Volcengine Ark- Availability
- 2 API providerslisted on models.dev
More from ByteDance Seed
About Seed 1.8
How much does Seed 1.8 cost?
Seed 1.8 costs $0.119 input / $1.19 output per million tokens (official Volcengine Ark API price). Cached input is $0.024 per million tokens. Requests over 32K tokens are billed at $0.178 input / $2.37 output. At a 3:1 input-to-output mix that is $0.386 per million tokens, cheaper than 67% of the 360 priced models we track.
What is the context window of Seed 1.8?
Seed 1.8 accepts up to 256,000 tokens per request and can write up to 64,000 tokens in one response.
How good is Seed 1.8?
Epoch AI has not published a Capabilities Index score for Seed 1.8 yet.
Is Seed 1.8 open source?
No. Seed 1.8 is proprietary; you use it through Volcengine Ark’s API or partner platforms.
What inputs does Seed 1.8 support?
Seed 1.8 accepts text and images and replies in text. It is a reasoning model with minimal, low, medium, high, xhigh and max effort settings, supports tool calling and can return structured JSON output.
When was Seed 1.8 released?
ByteDance Seed released Seed 1.8 on Dec 28, 2025.
What are the best alternatives to Seed 1.8?
The closest current models from other labs on capability, price and release date are GLM-4.6V (Z.ai (Zhipu), $0.30 / $0.90), Mercury 2 (Inception, $0.25 / $0.75), Qwen3 Coder Next (Alibaba (Qwen), $0.20 / $1.20) and Trinity Large Thinking (Arcee AI, $0.25 / $0.80).