Authentication
Create an active Secret Key in Developer settings. Keep it on your server; never embed it in browser or mobile code.
Authorization: Token YOUR_SECRET_KEY Accept: application/json Content-Type: application/json
Bearer authentication is also supported. Airtime and summaries are scoped to the account owning this key.
Saved vending method
Open Developer settings → Default vending method, choose Wallet or SIM and save. Data and airtime API calls without vending_type use this preference. An explicit vending_type overrides the saved choice. Existing accounts keep legacy behavior until a preference is saved.