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Credits & billing

Credits are prepaid US dollars of usage. Requests draw them down per token.

Credits

  • One credit is one US dollar of usage. Balances and charges are kept to the nano-dollar ($0.000000001).
  • Each model has a posted price per million input, cached-input and output tokens, listed on the models page and returned by GET /v1/models.
  • A request costs its tokens at those prices, rounded up to the next nano-dollar.
  • Some providers bill long prompts at higher prices (GPT-6 Astra above 272,000 prompt tokens, Grok 4.6 from 200,000). On those models a request over the limit costs the long-prompt prices for all of its tokens, as the provider bills it; the models page lists them.
  • Reasoning (thinking) tokens are output tokens, billed at the output price whether or not the model returns them. Claude models think without returning the thinking.

What happens during a request

  • Reserve. Before the request reaches a model, its largest possible cost is set aside from your available balance. If that cannot be covered, the request is refused with 402 and nothing is charged.
  • Settle. When the request finishes, the reservation is released and the tokens actually used are charged. The model reports the exact token counts; if a stream is cut off before reporting them, the delivered tokens are estimated from the text (about four characters per token) and the request is marked as estimated in your usage log.
  • Failures. Requests the model rejects, and requests that fail before producing any output, cost nothing.

Can a balance go negative?

Yes, slightly. A request can use more prompt tokens than the reservation estimated. A deposit credited before its block is posted to Ethereum is taken back if Robinhood Chain drops the transaction. While the balance is at or below zero, new requests are refused until you add credits.

Spending limits

Give any API key a lifetime spending limit in the dashboard. Requests that would take the key past it are refused with 403 key_spend_limit, counting reservations of requests still running.

Adding credits

  • USDG or USDC on Robinhood Chain. $1 of credit per token, from your own wallet, with no fee from us. See Paying on Robinhood Chain.

Refunds and disputes

To ask for a refund of unused credits, contact @avenrotech on X.

Records

The dashboard shows every top-up, refund and adjustment under Billing, and every request with its tokens, cost and saving under Usage.