How to pay for AI API access with crypto — no card, no subscription, no account

x402 HTTP-402 quote/pay/replay explained, with verified numbers.

How to pay for AI API access with crypto — no card, no subscription, no account

Published November 9, 2026.

You can call 1,000+ AI models — ChatGPT, Claude, Gemini, Llama and more — paying per request in crypto, with no credit card, no subscription, and for one flow not even an account: NanoGPT (nano-gpt.com) implements the x402 protocol, so an unauthenticated API request returns an HTTP 402 “Payment Required” quote that you settle on-chain and replay. The minimum deposit is $0.10, and every crypto top-up gets credited with a 3% bonus.

The problem this solves

Most AI billing assumes you have an international credit card and want a $20/month subscription. A large slice of developers worldwide has neither: card-only checkouts exclude them, subscriptions overcharge light users, and autonomous agents have no one to type a card number for them. Crypto rails fix the payment part — but most “AI accepts crypto” stories are gift-card workarounds or one-coin checkout buttons. The interesting part of NanoGPT is that the payment is wired into the API protocol itself.

Pattern 1: pre-funded account, pay-as-you-go

Create an account, deposit from $0.10 in crypto (Monero, Bitcoin + Lightning, Nano, USDT, USDC, Zcash, Litecoin, Bitcoin Cash, Dash, ETH, SOL, TON and more), and get one balance across the model catalog. API pricing is at list price with no markup — the docs give the example that GPT-5.5 costs $5/$30 per million tokens at OpenAI and exactly the same there. Every crypto top-up gets a 3% bonus (credited 3% more than you pay); card payments are credited at face value. Chats stay stored on your device by default, and accounts are optional.

Pattern 2: accountless x402 per-request payments

This is the “machine pays machine” flow. Send your API request without any key but with the header x-x402: true. The server replies 402 Payment Required with a signed quote bound to the exact method, path, body hash, amount, and a 15-minute expiry. You pay the quote on-chain — supported rails include Nano, Base USDC (gasless EIP-3009 signature), Solana USDC, and Lightning via L402, which currently gets a 10% discount versus the normal quote. Then you replay the original request with the X-PAYMENT header and get your model response; settlement comes back in X-PAYMENT-RESPONSE. No signup, no deposit, no account anywhere in that loop. The machine-readable endpoint matrix is at GET /api/v1/x402/endpoints.

An honest note on privacy (the weak point, stated up front)

x402 payments in USDC are on-chain and therefore traceable; NanoGPT is no-KYC for crypto users, not an anonymity tool. And it is not the only crypto-friendly gateway — OpenRouter accepts USDC via Coinbase and Venice accepts BTC/USDC. What is genuinely rare here is the accountless multi-rail 402 flow plus the breadth of deposit coins: their own monthly merchant stats show Monero is actually the #1 rail by volume (38.55% in August 2026), ahead of Bitcoin + Lightning (26.90%) and USDT + USDC combined (18.39%).

Who this is for

Developers in regions or situations where card-only AI billing fails; light users who would waste a subscription; and anyone building agents that need to budget their own inference per request. If you want to try it, $0.10 is enough to make your first paid calls.

Sources

Disclosure

Some links in versions of this article on personal surfaces are a referral link: https://nano-gpt.com/r/BxtwRFD3 — it gives referred users 5% off eligible usage and pays the author a 10% commission on eligible usage (5% on subscriptions). It costs the reader nothing extra. The author is not affiliated with NanoGPT; every factual claim above links to a verifiable official source.


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