Top up
Add funds to your Nimbus account. Prepaid, no subscription, no commitment.
Nimbus runs on a prepaid balance. Every request debits the balance in real time at the rate on the pricing page — no invoices, no seat licenses, no minimum commit. When the balance hits zero, the gateway returns 402 insufficient_balance until you top up. Unused credit rolls over forever and is refundable within 30 days.
How to top up
- Sign in at nimbusapi.net/dashboard/billing.
- Click Add funds. Pick an amount — the presets are $10, $25, $50, $100, $500 — or enter a custom amount. Minimum is $10, no maximum.
- Pick a payment method (card, crypto, or wire). Complete checkout with the processor.
- The balance widget in the header updates the moment the payment clears. Every top-up is written to the balance ledger and appears on the next monthly invoice.
Payment methods
| Method | Processor | Minimum | Fees | Settlement | Notes |
|---|---|---|---|---|---|
| Card (Visa, Mastercard, Amex) | SellAuth | $10 | None on our side. Card issuer FX applies for non-USD cards. | Credited in under 60 seconds after 3DS clears. | Best default. Auto-topup available: set a threshold and refill amount in Billing settings. |
| Crypto (300+ coins) | NowPayments | $10 USD equivalent | Network gas paid by sender. No Nimbus fee. | Credited after 1 confirmation for BTC / LTC, 12 confirmations for ETH / USDT (ERC-20), 1 confirmation for USDT (TRC-20 / Solana). | Popular picks: BTC, ETH, USDT (TRC-20 is cheapest gas), LTC, SOL, USDC. Full coin list is chosen at checkout. |
| Wire transfer | FoogleGiber LLC (Mercury Bank) | $2,000 | Your bank's outgoing wire fee. We do not charge. | Same-day for domestic ACH+, 1–3 business days for SWIFT. | For teams that want a paid invoice on file. Contact billing@nimbusapi.net for wire instructions and a company W-9. |
What the billing UI looks like
The billing screen at /dashboard/billing has four cards:
- Balance — a big USD figure with a green up-arrow when the last change was a top-up, red down-arrow when the last change was spend. Below it: 7-day burn rate and projected runway.
- Add funds — preset chips ($10, $25, $50, $100, $500) plus a custom input. A radio row picks card, crypto, or wire. Clicking Add funds redirects to SellAuth / NowPayments or reveals wire instructions inline.
- Auto top-up — toggle. When ON: pick a threshold (default $20) and a refill amount (default $50). When the balance falls below threshold, we charge the last-used card and post the credit.
- Ledger — reverse-chronological list of every balance transaction with timestamp, delta, method, and running balance. Two filters: type (top-up, usage, refund, adjustment) and date range.
Check balance from the API
Any active API key can read the account balance. The response is USD dollars as a floating-point number.
curl -sS https://llm.nimbusapi.net/v1/account/balance \
-H "Authorization: Bearer $NIMBUS_API_KEY"Refund policy
Unused credit is refundable to the original payment method within 30 days of the last top-up, no questions. After 30 days, credit stays on your account indefinitely and can be spent on any model. To request a refund, email billing@nimbusapi.net from the email on file. Crypto refunds are paid in the same coin and network used to fund, at the current spot rate.
FAQ
Do credits expire?
No. Balance persists as long as the account exists.
Can I set a spend cap per API key?
Yes — see Cost caps. Independent from the account balance.
Is there sales tax?
US customers: no. Non-US customers: no VAT collected today; local reverse-charge rules apply. A W-9 and W-8BEN are on file — see Invoices.
Are there volume discounts?
Not on top-up. Every request is already 50% off retail. For $5k+/mo spend we can cut a custom rate — email sales@nimbusapi.net.