Quickstart — onboard to ZetaAPI in 30 seconds

From sign-up to your first call in three steps. Covers sign-in, getting an API key, and switching to ZetaAPI in Cursor / Claude Code / any OpenAI SDK.

Updated 2026-10-05

What you’ll get in 30 seconds

• An API key that can call Claude / GPT / Gemini and other mainstream models
• ZetaAPI set as the upstream in your usual tools (Cursor / Claude Code / OpenAI Python SDK)
• Real-time token usage and cost in the console

Step 1: Sign up & top up

1. Open the console and sign in with Google / GitHub / email
2. Your account is created automatically on first sign-in — no review beyond email
3. On the “Top up” page, add credit from $1 via card / Alipay / WeChat (a guide walks you through the first one)

Step 2: Create an API key

Go to the API Keys page in the console:

• Click Create key
• Give it a recognizable name (e.g. cursor-mac, claude-code-work)
• Copy the generated key (format sk-xxxxx..., shown in plaintext only once)

⚠️ The full key is shown only at creation. Save it immediately to 1Password / macOS Keychain / a .env file or other secure place.

Step 3: Switch the upstream

Option A: Cursor

Settings → Models → OpenAI API Key:

• API Key: paste sk-xxxxx
• Base URL (enable Override OpenAI Base URL): https://api.staging.cosmos-router.com/v1

After saving, Chat and Cmd+K all route through ZetaAPI. See the Cursor setup guide.

Option B: Claude Code

Add to ~/.zshrc or ~/.bashrc:

export ANTHROPIC_BASE_URL="https://api.staging.cosmos-router.com"
export ANTHROPIC_API_KEY="sk-xxxxx"
export CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING=1

After source, just run claude. See the Claude Code setup guide.

Option C: any OpenAI SDK

from openai import OpenAI

client = OpenAI(
    api_key="sk-xxxxx",
    base_url="https://api.staging.cosmos-router.com/v1",
)

resp = client.chat.completions.create(
    model="claude-sonnet-4-6",
    messages=[{"role": "user", "content": "Hello"}],
)
print(resp.choices[0].message.content)

The official Node.js SDK / LangChain / LlamaIndex / any client that supports a custom base_url works the same way.

Option D: Claude Desktop

In the Claude Desktop menu bar, open Developer → Configure Third-Party Inference…, choose Gateway, set the Base URL to https://api.staging.cosmos-router.com and the API key to sk-xxxxx, then save and restart to use Claude models in Cowork and Code. You need to enable Developer Mode first; see the Claude Desktop setup guide for the full steps.

Verify it worked

After your first call, go back to the console home and you should see:

• Today’s usage change from 0 to non-zero
• Recent calls showing your request (model, tokens, latency, status code)
• If there’s no update within 5 minutes, your key or base URL is misconfigured — see the FAQ

Next steps

• Per-tool setup → tool setup guides
• Understand pay-as-you-go + Prompt Cache → billing
• Endpoints, error codes, rate limits → API Reference