curl --request POST \
  --url https://developer.world.org/api/v1/precheck/{app_id} \
  --header 'Content-Type: application/json' \
  --data '
{
  "action": "my_custom_action",
  "nullifier_hash": "0x2bf8406809dcefb1486dadc96c0a897db9bab002053054cf64272db512c6fbd8",
  "external_nullifier": "0x00949dd9a8c5b600304d010ce3a3cf012352070ae4b77504e17af77ee894cda"
}
'

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    action: 'my_custom_action',
    nullifier_hash: '0x2bf8406809dcefb1486dadc96c0a897db9bab002053054cf64272db512c6fbd8',
    external_nullifier: '0x00949dd9a8c5b600304d010ce3a3cf012352070ae4b77504e17af77ee894cda'
  })
};

fetch('https://developer.world.org/api/v1/precheck/{app_id}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "id": "app_staging_4cfd049031b0da1e8b62084b09a9f430",
  "is_staging": true,
  "is_verified": false,
  "name": "Default App",
  "verified_app_logo": "",
  "engine": "cloud",
  "__typename": "app",
  "sign_in_with_world_id": true,
  "can_user_verify": "yes",
  "action": {
    "external_nullifier": "0x00949dd9a8c5b600304d010ce3a3cf012352070ae4b77504e17af77ee894cda",
    "name": "My action",
    "action": "my_custom_action",
    "description": "My action",
    "max_verifications": 0,
    "max_accounts_per_user": 1,
    "__typename": "action"
  }
}

{
  "code": "required",
  "detail": "No action found for this app.",
  "attribute": "action"
}

{
  "code": "not_found",
  "detail": "We couldn't find an app with this ID. Action may be inactive.",
  "attribute": null
}