What Are Credits?
Credits are ACN’s internal billing unit for API key–based calls. Instead of signing on-chain transactions for every API call, you pre-fund your account with credits and they’re deducted automatically as you use the platform. 1 credit = 1 micro-USDC = $0.000001 USD Credits are denominated in micro-USDC to allow precise billing for very small per-call charges without floating-point rounding issues.Conversion Reference
| Amount | Credits | USD |
|---|---|---|
| 1 credit | 1 | $0.000001 |
| 1,000 credits | 1,000 | $0.001 |
| 1 USDC equivalent | 1,000,000 | $1.00 |
| $10 top-up | 10,000,000 | $10.00 |
| $100 top-up | 100,000,000 | $100.00 |
0.002 USDC costs 2,000 credits.
How Credits Are Added
Credits are added to your account through:| Source | Transaction Type |
|---|---|
| Stripe top-up (USD) | deposit |
| Coupon code redemption | coupon_credit |
| Volume discount bonus | volume_discount |
| Admin grant (support, beta program) | admin_credit |
How Credits Are Spent
Every API call via API key goes through a reserve → settle cycle:- Reserve — Before execution, credits equal to the call cost are held (reserved). Your available balance decreases by this amount.
- Settle — After execution:
- Success (2xx) or client error (4xx): reservation is settled, credits are permanently consumed
- Provider failure (5xx) or timeout: reservation is released, credits return to your balance
Balance Properties
No Negative Balances
Your balance can never go below zero. If a call would cost more than your remaining balance, it’s rejected before reaching the provider with HTTP 402.No Expiry
Credits never expire. Unused credits carry over indefinitely.Reserved vs Available
During execution, some credits may be temporarily “reserved” (held). Your available balance is:Balance Precision
Credit balances are stored as exact integers (no floating point) to guarantee precision. The conversion between USDC and credits is:Credits vs X402 (On-Chain Payments)
| Credits | X402 | |
|---|---|---|
| Auth required | API key | Agent wallet |
| Funding | Stripe (USD) | USDC on Base |
| Payment timing | Pre-funded | Per-call on-chain |
| Requires wallet | No | Yes |
| Best for | Apps, developers, most agents | Fully autonomous wallet-native agents |