## 1. Create an Account

Sign up at [modelstack.cc/sign-up](https://modelstack.cc/sign-up) to create your account.

## 2. Get Your API Key

1. Go to your [Dashboard](https://modelstack.cc/dashboard)
2. Navigate to **API Keys**
3. Click **Create API Key**
4. Copy your key (starts with `sk_`)

<Warning>
  Store your API key securely. It won't be shown again after creation.
</Warning>

## 3. Make Your First Request

<CodeGroup>

```bash cURL
curl https://api.modelstack.cc/v1/chat/completions \
  -H "Authorization: Bearer your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6",
    "messages": [
      {"role": "user", "content": "What is ModelStack?"}
    ]
  }'
```

```python Python
from openai import OpenAI

client = OpenAI(
    api_key="your_api_key",
    base_url="https://api.modelstack.cc/v1"
)

response = client.chat.completions.create(
    model="claude-sonnet-4-6",
    messages=[
        {"role": "user", "content": "What is ModelStack?"}
    ]
)

print(response.choices[0].message.content)
```

```javascript Node.js
import OpenAI from 'openai'

const client = new OpenAI({
  apiKey: 'your_api_key',
  baseURL: 'https://api.modelstack.cc/v1',
})

const response = await client.chat.completions.create({
  model: 'claude-sonnet-4-6',
  messages: [{ role: 'user', content: 'What is ModelStack?' }],
})

console.log(response.choices[0].message.content)
```

</CodeGroup>

## 4. Try Different Models

Switch models by changing the `model` parameter — no other code changes needed:

```python
# Use Claude
response = client.chat.completions.create(
    model="claude-sonnet-4-6",
    messages=[{"role": "user", "content": "Hello!"}]
)

# Use GPT-5.4
response = client.chat.completions.create(
    model="gpt-5.4",
    messages=[{"role": "user", "content": "Hello!"}]
)

# Use Gemini
response = client.chat.completions.create(
    model="gemini-3.1-pro",
    messages=[{"role": "user", "content": "Hello!"}]
)

# Use DeepSeek
response = client.chat.completions.create(
    model="deepseek-v3.2",
    messages=[{"role": "user", "content": "Hello!"}]
)
```

## Next Steps

<CardGroup cols={2}>
  <Card title="API Reference" icon="code" href="/docs/api-reference/overview">
    Learn about all available endpoints and parameters.
  </Card>
  <Card
    title="Supported Models"
    icon="neurology"
    href="/docs/models/supported-models"
  >
    Browse the full catalog of 50+ models with pricing.
  </Card>
  <Card title="Billing & Balance" icon="credit_card" href="/docs/billing/balance">
    Understand prepaid balance and pay-as-you-go billing.
  </Card>
  <Card title="SDK Integration" icon="cable" href="/docs/sdks/openai-sdk">
    Integrate with OpenAI, Anthropic, or other SDKs.
  </Card>
</CardGroup>