Account & Balance

Every request is billed against your account balance. These two endpoints let you read that balance and confirm which key you are authenticating with.

Check balance

GET /v1/balance

curl -X GET "https://api.zelnum.com/api/v1/balance" \
  -H "X-API-Key: YOUR_KEY_HERE"

{
  "balance": "5.230000"
}

Field	Type	Description
balance	string	Available balance in USD, fixed to 6 decimal places.

Note

The balance is returned as a string, not a JSON number, so no precision is lost before you do arithmetic on it.

Inspect the active API key

GET /v1/api-key

curl -X GET "https://api.zelnum.com/api/v1/api-key" \
  -H "X-API-Key: YOUR_KEY_HERE"

{
  "api_key_id": 12,
  "masked_key": "ck_xxxxxxxxx…****",
  "last_used": "2026-09-12T09:14:03.000000Z",
  "created_at": "2026-08-30T11:02:44.000000Z"
}

Field	Type	Description
api_key_id	integer	Identifier of the key, useful in support requests.
masked_key	string	Masked prefix. The plaintext key is never returned here.
last_used	string | null	When the key was last used, written at most once every five minutes — see Security.
created_at	string	When the key was created.

The endpoint reports the newest active key on the account, not an inventory. An account can hold several active keys; the Console lists them all — see Security for how rotation works.

If the account has no active key:

{
  "api_key": null,
  "message": "No API key found. Please regenerate."
}

Errors

Status	code	Cause
401	unauthorized	Missing, invalid or inactive key.
403	account_banned	The account has been suspended.
429	—	Rate limit reached — see Rate Limits.

Both endpoints share the general bucket: 60 requests / minute per API key.