Seed-OSS

About

What Seed-OSS is

👋 Hi, everyone! We are <bByteDance Seed Team.</b You can get to know us better through the following channels👇 Seed-OSS Open-Source Models [!NOTE] This model card is dedicated to the Seed-OSS-36B-Base-Instruct model. News - [2025/08/20]🔥We release Seed-OSS-36B-Base (both with and without synthetic data versions) and Seed-OSS-36B-Instruct. Introduction Seed-OSS is a series of open-source large language models developed by ByteDance's Seed Team, designed for powerful long-context, reasoning, agent and general capabilities, and versatile developer-friendly features. Although trained with only 12T tokens, Seed-OSS achieves excellent performance on several popular open benchmarks. We release this series of models to the open-source community under the Apache-2.0 license. [!NOTE] Seed-OSS is primarily optimized for international (i18n) use cases. Key Features - Flexible Control of Thinking Budget: Allowing users to flexibly adjust the reasoning length as needed. This capability of dynamically controlling the reasoning length enhances inference efficiency in practical application scenarios. - Enhanced Reasoning Capability: Specifically optimized for reasoning tasks while maintaining balanced and excellent general capabilities. - Agentic Intelligence: Performs exceptionally well in agentic tasks such as tool-using and issue resolving. - Research-Friendly: Given that the inclusion of synthetic instruction data in pre-training may affect the post-training research, we released pre-trained models both with and without instruction data, providing the research community with more diverse options. - Native Long Context: Trained with up-to-512K long context natively. Model Summary Seed-OSS adopts the popular causal language model architecture with RoPE, GQA attention, RMSNorm and SwiGLU activation. Evaluation Results Seed-OSS-36B-Base Incorporating synthetic instruction data into pretraining leads to improved performance on most benchmarks. We adopt the version augmented with synthetic instruction data (i.e., w/ syn.) as Seed-OSS-36B-Base. We also release Seed-OSS-36B-Base-woSyn trained without such data (i.e., w/o syn.), offering the community a high-performance foundation mo

Summarised from the published model card. Read the full card on the HuggingFace links below.

Specifications

What it is

How it works

How language models work

Variants

Sizes & precisions

Open weights ship in several sizes and precisions. One page, all the variants — pick the one that fits your GPU. VRAM figures are estimates from model size.

Using it via the API

Call it like any OpenAI endpoint

Once AxForge deploys seed-oss for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (seed-oss below is illustrative; you get the exact model name on deployment.)

$ curl -sS https://api.axforge.ai/v1/chat/completions \
  -H "Authorization: Bearer $AXFORGE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"seed-oss","messages":[{"role":"user","content":"Hello"}]}'

Details

Languages, data & research

Licence

Open weights

Sources

Weights & code

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