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/27/transactions` behind the x402 payment protocol. When called without payment, it returns a 402 challenge requesting USDC on the Base network. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 per request.
The provider site (lowpaymentfee.com) advertises a broad suite of x402-gated 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 the same $0.02/request price point. However, the specific endpoint listed here (`/api/v1/cards/27/transactions`) is not explicitly documented on the provider's landing page among those categories. Its title "Premium API Access" and its path suggest it relates to card transaction data, but no further documentation, request schema, or response schema is available.
Payment settles in USDC (contract `0x8335...2913`) on Base to address `0x1A2B...85F3`. The x402 challenge uses the "exact" scheme with a 300-second timeout. No API keys or rate limits are advertised. Documentation pages (/docs, /api, /pricing, /README) all returned only a "Connect wallet" prompt with no substantive content.
Capabilities
Use cases
- —Retrieving card transaction records via a pay-per-call model
- —Programmatic access to card transaction data without API key management
- —Agent-driven financial data retrieval settled in USDC on Base
Fit
Best for
- —Developers wanting keyless, pay-per-use card transaction data
- —AI agents that can settle x402 payments on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or response schemas before integrating
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/27/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02/request in USDC on Base). However, there is no request or response schema, no documentation beyond a wallet-connect prompt, and the specific endpoint path (/api/v1/cards/27/transactions) is not described anywhere on the provider site. This is effectively a stub listing.
Warnings
- —No request or response schema available — input/output format is unknown
- —The endpoint path /api/v1/cards/27/transactions is not listed among the provider's documented APIs
- —All documentation pages (/docs, /api, /pricing, /README) returned only 'Connect wallet' with no content
- —The hardcoded card ID '27' in the path suggests this may be a specific resource rather than a general-purpose API
- —No OpenAPI spec, ai-plugin manifest, or agents.txt found
Citations
- —The x402 challenge requests 20,000 base units of USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/cards/27/transactions
- —The provider advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Basehttps://lowpaymentfee.com
- —Documentation pages return only a 'Connect wallet' prompt with no substantive contenthttps://lowpaymentfee.com/docs