# BigModel.io documentation overview

> BigModel.io is a global model API platform. Learn the OpenAI- and Anthropic-compatible APIs it serves, how keys, groups, models and USD balance fit together, and where to find each guide.

Web version: https://bigmodel.io/docs/overview · Updated 2026-10-18

BigModel.io is a global model API platform: one API key for leading AI models, over the OpenAI and Anthropic protocols your tools already speak.

- **One key, two protocols.** Use the same key with OpenAI SDKs and with Anthropic clients such as Claude Code.
- **Priced in US dollars.** Model pages show the per-token price next to the official price.
- **Pay without an overseas card.** Top up with Alipay or USDT, among the methods shown at checkout.
- **Built for coding agents.** Guides for Claude Code, Codex CLI, Cursor and other tools.
- **Public status page.** Availability and latency per model at [/status](https://bigmodel.io/status).

Text models you can call today come from the GLM (Zhipu), DeepSeek, Kimi (Moonshot AI), MiniMax and Doubao (ByteDance) families. Image, video and audio models include Seedance, GPT Image, Qwen-Image, Kling, Vidu, Grok Imagine, Suno and more (see the [multimodal overview](https://bigmodel.io/docs/multimodal-overview)). The [model catalog](https://bigmodel.io/models) always has the current list. Text models from other families, such as Claude, GPT, Gemini and Qwen, are not available yet; the catalog marks any that are coming soon.

| You want to | Start here |
|---|---|
| Send a first request in a few minutes | [API quickstart](https://bigmodel.io/docs/quickstart) |
| Use a coding tool such as Claude Code or Cursor | [Claude Code](https://bigmodel.io/docs/claude-code), [Cursor](https://bigmodel.io/docs/cursor), [Codex CLI](https://bigmodel.io/docs/codex-cli) |
| Move existing OpenRouter code | [Migrate from OpenRouter](https://bigmodel.io/docs/migrate-from-openrouter) |
| Understand charges and top-ups | [Billing & top-ups](https://bigmodel.io/docs/billing) |
| Decode an error response | [Errors](https://bigmodel.io/docs/errors) |

## Two protocols, one gateway

The same key works on both protocols, subject to what the key's group serves (see below).

| Protocol | Base URL to configure | Main endpoints |
|---|---|---|
| OpenAI-compatible | `https://bigmodel.io/v1` | `POST /v1/chat/completions`, `POST /v1/responses`, `GET /v1/models` |
| Anthropic-compatible | `https://bigmodel.io` | `POST /v1/messages`, `POST /v1/messages/count_tokens` (the client adds `/v1`) |

Other endpoints: `GET /v1/usage` reports the key's balance and limits, image, video, avatar, speech and music models use `/v1/images/*`, `/v1/videos` and `/v1/audio/*`, and `/v1/workflows/short-drama` turns a script into clips (see the [multimodal overview](https://bigmodel.io/docs/multimodal-overview)).

```bash
curl https://bigmodel.io/v1/chat/completions \
  -H "Authorization: Bearer $BIGMODEL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"glm-5.3","messages":[{"role":"user","content":"Hello!"}]}'
```

## Core concepts

**API key.** Created in the console under [API Keys](https://bigmodel.io/keys). A key looks like `sk-` followed by 64 hex characters. You can view and copy the full key there at any time. Each key can have its own quota, spend windows, expiry and IP rules. See [Authentication](https://bigmodel.io/docs/authentication).

**Group.** Every key belongs to one group. The group decides which models and endpoints the key can use and which rate multiplier applies to its charges. Some groups (for example GLM or DeepSeek groups) serve only `/v1/chat/completions`; their keys get a 404 on `/v1/messages` and `/v1/responses`.

**Model ID.** Plain lowercase IDs that keep their dots, such as `glm-5.3`, `kimi-k3` or `deepseek-v4-pro`. Copy them from the [model catalog](https://bigmodel.io/models). Availability depends on the key's group; `GET /v1/models` lists what your key can call.

**Balance.** Your account holds a USD balance. Each request is charged by tokens at the model's price times the group multiplier. Paid models need a balance above zero; models priced at $0 can be called at a zero balance. New accounts get free trial credit; the amount is shown in the console. Plans (subscriptions) are an alternative for keys in a plan group. See [Billing & top-ups](https://bigmodel.io/docs/billing).

**Usage.** Every request appears in [Usage](https://bigmodel.io/usage) with tokens, cost, model and timing. `GET /v1/usage` returns the same totals for one key.

## Map of the docs

- **Get started:** [Quickstart](https://bigmodel.io/docs/quickstart) · [Authentication](https://bigmodel.io/docs/authentication) · [Billing & top-ups](https://bigmodel.io/docs/billing) · [Trial credit & free models](https://bigmodel.io/docs/free-credits) · [Limits & rate limits](https://bigmodel.io/docs/rate-limits) · [Errors](https://bigmodel.io/docs/errors) · [FAQ](https://bigmodel.io/docs/faq)
- **Capabilities:** [Streaming](https://bigmodel.io/docs/streaming) · [Tool calling](https://bigmodel.io/docs/tool-calling) · [Image input](https://bigmodel.io/docs/vision) · [Multimodal overview](https://bigmodel.io/docs/multimodal-overview) · [Short-drama workflow](https://bigmodel.io/docs/short-drama-workflow) · [Prompt caching](https://bigmodel.io/docs/prompt-caching) · [Model IDs](https://bigmodel.io/docs/model-ids) · [Per-key limits & budgets](https://bigmodel.io/docs/key-limits) · [Data & privacy](https://bigmodel.io/docs/data-privacy)
- **Coding tools:** [Claude Code](https://bigmodel.io/docs/claude-code) · [Cursor](https://bigmodel.io/docs/cursor) · [Codex CLI](https://bigmodel.io/docs/codex-cli) · [OpenCode](https://bigmodel.io/docs/opencode) · [Cline](https://bigmodel.io/docs/cline)
- **SDKs and migration:** [OpenAI SDK](https://bigmodel.io/docs/openai-sdk-langchain) · [Anthropic SDK](https://bigmodel.io/docs/anthropic-sdk) · [Migrate from OpenRouter](https://bigmodel.io/docs/migrate-from-openrouter)
- **API reference:** [API overview](https://bigmodel.io/docs/api-overview)

## Check the service

The [status page](https://bigmodel.io/status) shows availability, latency and time to first token per model. Questions about your account go to [Support](https://bigmodel.io/support) or support@bigmodel.io.

## Troubleshooting

**Not sure which base URL a tool wants.** If it asks for a base URL on the OpenAI protocol, use `https://bigmodel.io/v1`; Anthropic clients take `https://bigmodel.io`. See the [quickstart](https://bigmodel.io/docs/quickstart).

**A model works in the catalog but not with your key.** The key's group does not serve it, and the request returns 503 `No available accounts`. See [Errors](https://bigmodel.io/docs/errors).

## Related

- [API quickstart](https://bigmodel.io/docs/quickstart)
- [FAQ](https://bigmodel.io/docs/faq)
- [Model catalog](https://bigmodel.io/models) and [pricing](https://bigmodel.io/pricing)