x402-gated card-transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a POST route at `/api/v1/cards/79/transactions` behind an x402 payment challenge. It is part of a broader platform that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all gated via the x402 protocol on the Base network, settled in USDC.
The specific endpoint listed here is labeled "Premium API Access" and relates to card transactions (resource path `/api/v1/cards/79/transactions`). However, the platform provides no public documentation, OpenAPI schema, or example request/response payloads for this or any other endpoint — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. As a result, the exact input parameters, response format, and functional behavior of this endpoint are unknown.
Pricing is $0.02 per request (the x402 challenge advertises a maxAmountRequired of 20000 base units of USDC on Base, which is 20000 / 10^6 = $0.02). Payment is made via the x402 exact scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3. No API keys, rate limits, or subscriptions are required — access is purely pay-per-call. The endpoint is live and returns a proper 402 challenge.
Capabilities
Use cases
- —Querying card transaction data on a per-call payment basis
- —Integrating card transaction lookups into agent workflows without API key management
- —Programmatic access to card-level transaction records settled via crypto micropayments
Fit
Best for
- —Agents or services that need on-demand card transaction data without subscription commitments
- —Developers exploring x402 pay-per-call patterns on Base
- —Low-volume or bursty workloads where flat per-request pricing is preferable
Not for
- —Users who need detailed API documentation or schema guarantees before integrating
- —High-volume production workloads requiring SLAs, rate-limit guarantees, or support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/79/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is zero documentation: no OpenAPI schema, no example requests or responses, no description of what the endpoint actually returns. The docs/pricing/README pages are all empty beyond a wallet-connect prompt. The endpoint's purpose ('cards/79/transactions') is only inferable from the URL path. This is effectively a stub listing.
Warnings
- —No API documentation, OpenAPI schema, or example payloads are available for this endpoint.
- —The exact functionality of '/api/v1/cards/79/transactions' is unknown — the description 'Premium API Access' is generic and uninformative.
- —All documentation pages (docs, api, pricing, README) render only 'Connect wallet' with no content.
- —The hardcoded '/79/' in the path suggests this may be a specific card resource rather than a general-purpose endpoint.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/79/transactions
- —Platform pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/79/transactions
- —Docs, API, pricing, and README pages all show only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs