curl --request POST \
  --url https://api.interchange.io/api/v2/storefront/inventory-sources/{sourceId}/modular/reservations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "mediaBuyId": "<string>",
  "buyerCustomerId": 4503599627370495,
  "requestedImpressions": 4503599627370495
}
'

import requests

url = "https://api.interchange.io/api/v2/storefront/inventory-sources/{sourceId}/modular/reservations"

payload = {
    "mediaBuyId": "<string>",
    "buyerCustomerId": 4503599627370495,
    "requestedImpressions": 4503599627370495
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    mediaBuyId: '<string>',
    buyerCustomerId: 4503599627370495,
    requestedImpressions: 4503599627370495
  })
};

fetch('https://api.interchange.io/api/v2/storefront/inventory-sources/{sourceId}/modular/reservations', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "bookingId": "<string>",
  "availId": "<string>",
  "mediaBuyId": "<string>",
  "packageId": "<string>",
  "requestedImpressions": 4503599627370495,
  "status": "HELD"
}

{
  "data": null,
  "error": {
    "code": "<string>",
    "message": "<string>",
    "field": "<string>",
    "details": {}
  }
}

{
  "data": null,
  "error": {
    "code": "<string>",
    "message": "<string>",
    "field": "<string>",
    "details": {}
  }
}

{
  "data": null,
  "error": {
    "code": "<string>",
    "message": "<string>",
    "field": "<string>",
    "details": {}
  }
}