Authentication and API keys

Every request to BigModel.io is authenticated with an API key from the console. Send it in a header; the gateway checks it before routing the request to a model.

If several are present, Authorization wins, then x-api-key, then x-goog-api-key. The Bearer scheme is case-insensitive.

#Create a key

1. Sign in and open API Keys.
2. Click create, enter a name and choose a group. The group decides which models and endpoints the key can call and its rate multiplier.
3. Optionally set a quota, spend windows, expiry and IP rules (see below).
4. Copy the key and store it as an environment variable.

export BIGMODEL_API_KEY="sk-..."

Keys look like sk- followed by 64 hex characters. You can also enter a custom key of at least 16 characters using letters, digits, _ and -.

The key is not shown only once. The table shows a masked form (first 6 and last 4 characters), and the copy button copies the full key at any time. Anyone with the key can spend your balance, so keep it server-side and out of repositories and browser code.

#Send the key

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":"ping"}]}'

import os
from openai import OpenAI

client = OpenAI(base_url="https://bigmodel.io/v1", api_key=os.environ["BIGMODEL_API_KEY"])

import Anthropic from "@anthropic-ai/sdk";

// The Anthropic SDK sends x-api-key; the root URL has no /v1.
const client = new Anthropic({ baseURL: "https://bigmodel.io", apiKey: process.env.BIGMODEL_API_KEY });

Do not put the key in the URL. ?key= or ?api_key= is rejected with 400 api_key_in_query_deprecated.

#Groups

A key belongs to exactly one group, and you choose it when you create the key. The group sets:

• Models. Only models the group serves can be called. There is no per-key model allow-list.
• Endpoints. GLM and DeepSeek groups serve only /v1/chat/completions; /v1/messages, /v1/messages/count_tokens and /v1/responses return 404 for them. Anthropic groups serve /v1/messages natively and convert Chat Completions. OpenAI groups serve Chat Completions and Responses, and convert /v1/messages if the group allows it.
• Price multiplier. Charges are the model price times the group's multiplier. A personal rate can replace it.

A key with no group returns 403 permission_error "API Key is not assigned to any group". Edit the key and choose a group.

#Per-key settings

Each key can be edited in API Keys:

The ACCESS_DENIED message is deliberately vague; if you set IP rules, check them first. Use separate keys per app or environment so you can cap, rotate or disable one without touching the others. Details: Per-key limits & budgets.

#Verify the setup

GET /v1/usage checks the key without spending anything and works even when the key is expired or exhausted:

curl https://bigmodel.io/v1/usage \
  -H "Authorization: Bearer $BIGMODEL_API_KEY"

isValid, status, the quota or balance, and expires_at tell you whether the key will be accepted. The Test key action in API Keys runs a test request from the console.

#Troubleshooting

401 API_KEY_REQUIRED. No key reached the gateway. Check the header name, and that the environment variable is set in the process that sends the request.

401 INVALID_API_KEY. The key is wrong or deleted. Copy it again from API Keys; watch for stray spaces or quotes.

401 USER_NOT_FOUND or USER_INACTIVE. The account that owns the key is missing or not active. Contact Support.

403 ACCESS_DENIED. The request IP is blocked by the key's IP whitelist or blacklist.

403 permission_error "not assigned to any group". Assign a group to the key.

404 ... platform only supports /v1/chat/completions. The key's group is Chat Completions only. Use a key from another group for Messages or Responses clients.

403 INSUFFICIENT_BALANCE. Authentication succeeded, but the balance is zero or below. See Billing & top-ups.

#Related

• Errors
• Limits & rate limits
• Per-key limits & budgets
• API quickstart