# Paying BlitzAPI BlitzAPI accepts card payments only: wallet payments (x402, MPP stablecoins) are not offered. Cards pay for plan purchases; no crypto wallet is needed. This seller sells access on plans, not per call: buy a plan (`POST /plans/{planId}/purchase`), then call against it. Follow the identity requirements for your purchase amount. The priced `402 payment_required` you settle is the plan purchase; a bare call with no plan is refused with `401`, never a per-call price. ## Rails - [Card](https://agents.blitz-api.ai/zcj/53dmiccsw0d0/payment/card.md): plan purchases. No wallet needed; eligible hosted checkouts support browser agents with Link Pay Tokens (LPT), with human checkout as a fallback. ## The 402 body A priced 402 carries the exact `payment.amountUsd`, the `plan`, and, for a charge of $0.50 or more, a `card` block listing the card lanes for it, plus a `method="stripe"` challenge in the `www-authenticate` response header for shared payment tokens. ## Buying and extending plans Buying a plan needs a registered agent credential first, registered at [auth.md](https://agents.blitz-api.ai/zcj/53dmiccsw0d0/auth.md), presented as `Authorization: Bearer ` - or, on MPP where `Authorization` carries the `Payment` credential, as `ZC-Agent-Authorization: Bearer `. A bare purchase with no bearer returns `401 bearer_required` before any price is quoted; with the bearer you receive one priced 402 to settle. Plans on this storefront: - **Credits** - prepaid credit, $0.50 minimum per purchase, $99 maximum per purchase. Calls draw it down; top up with `POST /extend`. - Buy: `POST https://agents.blitz-api.ai/zcj/53dmiccsw0d0/plans/{planId}/purchase`. Credit plans take an amount (`{ "amountUsd": "25.000000" }`, a whole-cent value of at least the plan's `purchase.minimumUsd` and, when the plan sets one, at most `purchase.maximumUsd`); subscription plans take no amount (the base price is charged). - For a NEW card-funded credit purchase use `purchase.cardMinimumUsd`: it is the larger of the plan minimum and the $0.50 card floor, rounded up to whole cents. Card never lowers the plan minimum. A fixed-price plan priced under that floor carries `"cardEligible": false` and cannot be bought by card at all. - Purchases of plans whose `verifiedEmailPolicy` is `"requested"` or `"required"` share your human's verified email with this seller so it can tie what you bought to their account - at purchase when the claim already exists, or later once your human claims your credential. - Extend / top up: when a credit balance runs low or a call returns `usage_exhausted`, add credit with `POST https://agents.blitz-api.ai/zcj/53dmiccsw0d0/extend` and `{ "amountUsd": "10.000000" }` - the same one-402 payment. Your new balance returns as `access.remainingCreditUsd`. - Live prices and the exact `purchase.url` per plan are in [manifest.json](https://agents.blitz-api.ai/zcj/53dmiccsw0d0/manifest.json). ## Ceiling pricing - charging up to a maximum Some meters (e.g. output tokens) cannot be known before the work runs. The 402 challenge then lists the item as {"meterSlug", "maxQuantity"} and the payment amount is a CEILING, not the price you pay - it is the most you could ever be charged, and you pay only your actual usage once the work runs. By card, the ceiling is authorized up front and only your actual usage is captured; the rest of the authorization is released. A failed delivery charges nothing. Every paid response also carries a `zc-billing` header reconciling the numbers for that request: what you authorized (`authorizedUsd`), what you were actually charged (`chargedUsd`), and the remainder (`remainderUsd` + `remainderHandling`). `"status":"settling"` means settlement is still finishing and the final amounts are not stamped yet. A plan-funded response (drawing a prepaid balance, or covered by a subscription) carries the header in its plan shape instead: `fundingSource` ("credit" or "subscription"), `chargedUsd` = what your balance was actually debited for this request (zero when a flat subscription or included units covered it - never the notional metered cost), and `remainingCreditUsd` = your balance after the debit, when the plan tracks one. A delivered response with no `zc-billing` header billed nothing. Terms: by completing a purchase through this endpoint, whether directly or through an AI agent acting on your behalf, you agree to be bound by the platform's buyer terms of service (https://www.zeroclick.ai/legal/buyer-terms-of-service). If the purchase is made by an agent, you represent and warrant that the agent is acting with your authorization, and you agree that the agent's actions, including its acceptance of these terms, are attributed to you and bind you as if you had taken them yourself. Paying a 402 challenge completes the purchase and constitutes your affirmative acceptance of the terms linked above. The link travels in every payment challenge and receipt as `terms`. The full error reference is at [errors.md](https://agents.blitz-api.ai/zcj/53dmiccsw0d0/errors.md).