Getting started

Quickstart

Buy credit, create a capped key, and send your first GPT-5.5 request in minutes.

1. Create your account

Sign in with email, phone, or Google to open your dashboard.

2. Buy prepaid credit

Go to Dashboard → Billing, choose an amount from €10, and pay securely with Stripe.

3. Create a capped API key

Generate an X420 API key from the Dashboard. Copy it once and set the spending cap you want for that app or test.

4. Replace the base URL

Keep your OpenAI-style SDK and point it at the X420 endpoint:

from openai import OpenAI

client = OpenAI(
    base_url="https://api.x420.ai/v1",
    api_key="YOUR_X420_API_KEY",
)

response = client.chat.completions.create(
    model="openai/gpt-5.5",
    messages=[{"role": "user", "content": "Hello GPT-5.5"}],
)
print(response.choices[0].message.content)