Add your API key to the Authorization header:

Authorization: Bearer YOUR_API_KEY

Example request:

curl -X POST https://apimodels.app/api/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gemini-2.5-flash-image",
    "prompt": "A futuristic cityscape at sunset",
    "aspect_ratio": "16:9"
  }'