x402-gated card-transaction endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card transactions resource at `/api/v1/cards/97/transactions` behind an x402 payment challenge. The endpoint accepts POST requests and is settled on the Base network using USDC (contract 0x8335…2913). The maximum amount required per call is 20,000 base units of USDC, which with 6 decimals equals $0.02 per request.
The provider's landing page advertises a broad suite of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation) — all at $0.02 per request. However, this specific listing is for the `/api/v1/cards/97/transactions` path, which is labeled generically as "Premium API Access" with no further documentation on its request or response schema. The docs, pricing, and API pages behind the site all render only a "Connect wallet" prompt with no additional technical detail.
Without an OpenAPI spec, request/response examples, or documentation beyond the x402 challenge itself, the exact functionality of this card-transactions endpoint is unclear. It may relate to financial card transaction data, but this is speculative. The endpoint is confirmed live (returns a valid 402 challenge). No API keys or rate limits are advertised; access is purely pay-per-call via x402.
Capabilities
Use cases
- —Querying card transaction data via a pay-per-call model without API keys
- —Integrating card transaction lookups into agent workflows that support x402
- —Programmatic access to financial card data settled in USDC on Base
Fit
Best for
- —Agents or services that support x402 payment protocol
- —Users who want keyless, pay-per-request access to card transaction data
- —Developers building on Base who hold USDC
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume batch processing where per-request fees add up quickly
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/97/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but there is no OpenAPI spec, no request/response schema, and no documentation beyond a generic 'Premium API Access' label. The purpose of the /cards/97/transactions path is unclear and must be inferred. Docs pages render only a wallet-connect prompt.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —The exact functionality of /api/v1/cards/97/transactions is undocumented and unclear
- —All documentation pages (docs, pricing, API, README) render only a 'Connect wallet' prompt with no technical content
- —The endpoint path suggests card-specific transaction data but this is speculative
Citations
- —Endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/97/transactions
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/cards/97/transactions
- —All APIs priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com