Credits & Top-ups

Credits let you use the API without a monthly subscription. Top up your balance, and usage is deducted automatically until your credits run out.

All endpoints require authentication.

Top up credits

POST /api/billing/topup

Request body

Parameter	Type	Required	Description
`amount`	number	Yes	Top-up amount in USD (minimum $10)
`method`	string	Yes	`stripe`, `stripe_direct`, or `usdc`

Stripe top-up

curl -X POST https://api.cheapestinference.com/api/billing/topup \
  -H "Authorization: Bearer YOUR_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"amount": 50, "method": "stripe"}'

{
  "success": true,
  "data": {
    "sessionUrl": "https://checkout.stripe.com/c/pay/cs_live_...",
    "sessionId": "cs_live_..."
  }
}

USDC top-up

curl -X POST https://api.cheapestinference.com/api/billing/topup \
  -H "Authorization: Bearer YOUR_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"amount": 50, "method": "usdc"}'

{
  "success": true,
  "data": {
    "address": "0x...",
    "chain": "base",
    "amount": "50"
  }
}

Verify USDC top-up

POST /api/billing/verify-topup

After sending USDC on-chain, verify the transaction to credit your account.

Request body

Parameter	Type	Required	Description
`txHash`	string	Yes	Base L2 transaction hash
`amount`	number	Yes	Amount sent (must match)

Example

curl -X POST https://api.cheapestinference.com/api/billing/verify-topup \
  -H "Authorization: Bearer YOUR_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"txHash": "0xabc123...", "amount": 25}'

Response

{
  "success": true,
  "data": {
    "credited": 25,
    "balance": 75.00
  }
}

Check credit balance

GET /api/billing/credits

Returns your current credit balance and usage.

Example

curl https://api.cheapestinference.com/api/billing/credits \
  -H "Authorization: Bearer YOUR_AUTH_TOKEN"

Response

{
  "success": true,
  "data": {
    "totalTopUp": 100,
    "remaining": 74.50,
    "hasCreditKey": true,
    "creditKeyCount": 2,
    "userId": "ci_user_xxx"
  }
}

Field	Description
`totalTopUp`	Total amount you’ve ever topped up (number)
`remaining`	Current available balance in USD (number, real-time)
`hasCreditKey`	Whether you have at least one credit key
`creditKeyCount`	Number of active credit keys
`userId`	Internal user ID for budget tracking (`null` until first top-up)

How credits work

Credit key

After topping up, create a credit key via POST /api/keys/credit or from the dashboard. Credit keys use budget-based tracking instead of subscription-based rate limits.

The credit key has a 60 RPM rate limit
There is no token-per-minute limit — spend is tracked in USD
The system tracks max_budget and spend for the key
When spend >= max_budget, further requests fail with a budget error

Shared balance

All credit usage for your account goes through your single credit key. The balance is shared — if you use it from multiple applications, they all draw from the same pool.

Top-up accumulation

Each top-up adds to your existing budget:

Current max_budget: $50, spent: $20 (remaining: $30)
Top up $25
New max_budget: $75, spent: $20 (remaining: $55)

Credits vs. Subscriptions

	Subscription	Credits
Payment	Pool time-block subscription, from $39/mo (annual −15%)	$10+ per top-up
Rate limits	Unlimited during reserved blocks, 1 concurrent request per key	60 RPM only
Billing	Flat monthly/annual rate, unlimited usage within reserved hours	Pay per token used
Expiration	Renews each billing period; keys revoked when the period ends	Never expires, consumed until depleted
Key creation	Manual, after subscribing to a pool	Manual via API or dashboard after top-up

Pool subscriptions reserve 1–3 daily 8-hour UTC blocks (asia, europe, americas) — see the Unlimited Subscriptions API.

You can have both an active subscription and credits simultaneously. Subscription keys give unlimited access during reserved hours; credit keys use budget-based access.