x402-gated card-transactions endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com exposes a card transactions resource at `/api/v1/cards/6/transactions` behind the x402 payment protocol. It accepts POST requests and is settled on the Base network using USDC (contract 0x8335…2913). The x402 challenge advertises a maximum amount of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request — consistent with the site-wide flat pricing of $0.02/request.
The provider's landing page lists a broad catalog of pay-per-call APIs spanning data & analytics, AI/ML inference (sentiment, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints share the same $0.02 USDC pricing and x402 payment model with no API keys, no rate limits, and no minimum commitments.
Documentation is extremely thin — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawl. The specific purpose and data model of the `/api/v1/cards/6/transactions` endpoint (e.g., what "cards/6" refers to, what fields are accepted or returned) cannot be determined from the available material.
Capabilities
Use cases
- —Submitting or retrieving card transaction data via a pay-per-call model
- —Integrating x402 micropayments into agent workflows that need card transaction information
- —Programmatic access to card transaction records without traditional API key management
Fit
Best for
- —Developers experimenting with x402 payment-gated APIs
- —Agents that need on-demand, keyless API access settled in USDC on Base
- —Low-volume or sporadic usage where $0.02/request flat pricing is attractive
Not for
- —Production workloads requiring well-documented request/response schemas
- —High-volume use cases where per-request pricing adds up quickly
- —Users who need detailed API documentation or SDKs before integrating
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/6/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (402 challenge confirmed) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and the purpose of '/api/v1/cards/6/transactions' is unexplained. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or schema available — request and response formats are unknown
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no technical content
- —The meaning of 'cards/6' in the URL path is unclear — it may be a hardcoded demo resource
- —No examples of successful responses are available from the crawl
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units in USDC on Base networkhttps://lowpaymentfee.com/api/v1/cards/6/transactions
- —Site-wide pricing is $0.02 per request with no API keys, no rate limits, and instant access on Basehttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/6/transactions