Developer FAQ: API keys, base URL, billing

Short answers to the questions we get most. Each links to the page with details.

#Which base URL do I use?

OpenAI-style clients and SDKs: https://bigmodel.io/v1. Anthropic-style clients (Claude Code, Anthropic SDK): https://bigmodel.io without /v1, because the client adds /v1/messages itself. Adding /v1 twice gives a 404. See the quickstart.

#I lost my API key. Do I need a new one?

No. Open API Keys and use the copy button; it copies the full key at any time. If you think the key leaked, disable it and create a new one. See Authentication.

#Why does my model return 503 "No available accounts"?

That is how BigModel.io reports a model the key cannot use: either the ID is mistyped, or the key's group does not serve it. Copy the ID from the catalog (lowercase, dots kept) and check GET /v1/models. See Errors.

#What is a group, and why does my key get 404 on /v1/messages?

Every key belongs to a group, which decides the models, endpoints and price multiplier. GLM and DeepSeek groups serve only /v1/chat/completions, so Claude Code (Messages) and Codex CLI (Responses) need a key from a group that serves those endpoints.

#Can I use Claude Code with GLM, Kimi or DeepSeek?

Yes. Set ANTHROPIC_BASE_URL=https://bigmodel.io, ANTHROPIC_AUTH_TOKEN to your key and ANTHROPIC_MODEL to a model ID, using a key whose group serves /v1/messages. See Claude Code.

#Why do I get 403 when my balance is zero?

Paid models and endpoints such as GET /v1/models need a balance above zero; with a zero balance they return 403. Models priced at $0 stay callable on the chat, messages and responses endpoints, with a per-minute limit while the balance is zero. Top up any amount to use paid models. See Trial credit & free models.

#How am I charged?

In USD per token: input, output, cache read and cache write tokens at the model's price, times your group's multiplier. Failed requests are not charged. Every charge is listed in Usage. See Billing & top-ups.

#How can I pay?

In Billing. Methods are shown at checkout, for example Alipay and USDT (TRC20, ERC20, BEP20). Your balance is always in USD.

#Can I get a refund?

Unused plans can be refunded within 24 hours of purchase. USDT payments are not refundable, and promotional credit has no cash value. See the refund policy.

#Can I limit how much one key spends?

Yes. Each key can have a USD quota and 5-hour, 1-day and 7-day spend windows, plus an expiry date and IP rules. Windows are fixed, not rolling. See Limits & rate limits.

#I am getting 429 errors. What should I do?

Read the error code. API_KEY_QUOTA_EXHAUSTED, USAGE_LIMIT_EXCEEDED and window messages ("限额已用完") will not clear by retrying. "Too many pending requests" and "Concurrency limit exceeded" mean too many parallel requests; RPM limits send Retry-After. See Limits & rate limits.

#Does my OpenRouter code work?

Mostly, by changing the base URL and key. provider/model IDs, the models fallback array and HTTP-Referer / X-Title are accepted; the provider object, transforms and route are ignored. See Migrate from OpenRouter.

#Are my prompts stored or used for training?

Prompts and outputs of successful requests pass through to the model provider and are not kept after delivery. Bodies of failed requests are kept up to 30 days, with credentials removed, for troubleshooting. Prompts are not used for training. The provider may retain data under its own terms. See the privacy policy.

#How do I check whether a model is up?

The status page shows availability, latency and time to first token per model over 24 hours, 7 days and 30 days.

#How do I contact support?

Use Support in the console or email support@bigmodel.io. Replies within one business day. Include the X-Request-ID, time, model, endpoint and the error body; see Errors.

#Troubleshooting

My question is not here. Search the docs, then ask Support.

An answer here disagrees with what I see. Trust the error message and console, and tell us so we can fix the page.

#Related

• Overview
• API quickstart
• Errors