Billing

$25 free credit on sign-up. Add more via Stripe when you need it.

Free credit

Every new account starts with $25 in free credit. Tier 1 is always free and never deducts from your balance. Tiers 2–4 deduct from your balance per request.

Add credits

Create a Stripe Checkout session to top up your balance. Your user clicks the returned URL to complete payment.

POST

/v1/billing/add-credits

Create a Stripe Checkout session to add credits

Parameter	Type	Required	Description
amount_cents	integer	Yes	Amount to add in cents. Minimum 1000 ($10).

json

// Request
{
  "amount_cents": 2500
}

// Response
{
  "url": "https://checkout.stripe.com/..."
}

Redirect or open url for the user to complete payment. Credits are applied as soon as the payment is confirmed. Your first completed top-up also removes the free-tier daily request cap and saves your card for reuse, so auto-charge can be enabled afterwards.

Auto-charge

Keep your balance funded automatically. When the balance drops below threshold_cents, TierUp charges your saved payment method for amount_cents. A saved payment method is required — completing any top-up saves your card. As a safety ceiling, auto-charge never fires more than 3 times per day (UTC) and never twice within 15 minutes.

POST

/v1/billing/auto-charge

Configure automatic top-ups when balance runs low

Parameter	Type	Required	Description
threshold_cents	integer	Yes	Trigger a top-up when balance drops below this amount (in cents).
amount_cents	integer	Yes	Amount to charge in cents. Minimum 1000 ($10), maximum 50000 ($500).

json

// Charge $25 when balance drops below $5
{
  "threshold_cents": 500,
  "amount_cents": 2500
}

Transaction history

Returns the last 50 transactions on your account.

GET

/v1/billing/transactions

Retrieve the last 50 transactions

json

{
  "transactions": [
    {
      "id": "txn_01HXYZ",
      "type": "top_up",
      "amount_cents": 2500,
      "created_at": "2026-04-04T10:00:00Z"
    },
    {
      "id": "txn_01HWXY",
      "type": "usage",
      "amount_cents": -12,
      "created_at": "2026-04-04T09:45:00Z"
    }
  ]
}

Balance at $0? Paid-tier requests (Tiers 2–4) return 402 Payment Required unless auto-charge is enabled with a saved card. Tier 1 remains free and continues to work regardless of your balance.