China AI Hub
API / ark
ark API
Provider: bytedance · Type: official
ark is an API by bytedance, served at https://ark.cn-beijing.volces.com/api/v3 for official models, exposing Doubao Seed 2.1 Pro, Doubao Seed 2.1 Turbo, Doubao Seed Evolving.
| Key fact | Value |
|---|---|
| Endpoint | https://ark.cn-beijing.volces.com/api/v3 |
| Authentication | API key (Bearer token); AK/SK also documented for the chat API |
| Streaming | Yes |
| Function calling | Unknown |
| Tool calling | Yes |
| Structured output | Yes |
| Vision | Yes |
| Audio | Unknown |
| Rate limits | Flagship Doubao models: 500 RPM / 1,000,000 TPM (as of 2026-09-20) |
| Regions | china |
| Cloud providers | Volcengine |
| Documentation | https://docs.volcengine.com/docs/ark |
Context limits
| Model | Input limit | Output limit |
|---|---|---|
| doubao-seed-2-1-pro | 1,048,576 | 262,144 |
| doubao-seed-evolving | 1,048,576 | 262,144 |
| doubao-seed-2-1-turbo | 262,144 | 262,144 |
Volcengine Ark is ByteDance’s official AI API platform, serving the Doubao Seed model family from the
cn-beijing region. It exposes a Responses API (POST /api/v3/responses) and an OpenAI-compatible Chat
API (POST /api/v3/chat/completions), both with SSE streaming. Authentication uses a Bearer API key
obtained from the Ark console; the chat API additionally documents AK/SK access-key authentication.
The API supports thinking toggles (thinking={"type":"enabled"|"disabled"}, reasoning_effort),
tool calling and structured output (json_schema recommended). Chat API messages can carry text, image,
video and audio content; a Files API handles uploads of video, image and PDF inputs. Third-party models
(such as DeepSeek and GLM) are also hosted on Ark.
Provider
Models served
Pricing
Sources
Data interpretation
| Field | Value | Evidence type |
|---|---|---|
| Endpoint | https://ark.cn-beijing.volces.com/api/v3 | Official |
| Authentication | API key (Bearer token); AK/SK also documented for the chat API | Official |
| Capabilities | Streaming, Tool calling, Structured output, Vision | Official |
| Models served | 3 models in the database | China AI Hub analysis |
Evidence types: Official = vendor documentation or official pages. China AI Hub analysis = derived from the database itself. See the sourcing policy.
What is the ark API endpoint?
The ark API endpoint is https://ark.cn-beijing.volces.com/api/v3.
How do you authenticate with the ark API?
API key (Bearer token); AK/SK also documented for the chat API.
What are the context limits of the ark API?
doubao-seed-2-1-pro: 1,048,576 in / 262,144 out; doubao-seed-evolving: 1,048,576 in / 262,144 out; doubao-seed-2-1-turbo: 262,144 in / 262,144 out.
Where does China AI Hub get its ark API data?
From 3 sources, last verified 2026-09-20.