x402-gated transaction receipt endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a transaction receipt (resource ID 372) behind an x402 paywall. The endpoint accepts POST requests and returns JSON. Payment is settled on the Base network using USDC (contract 0x8335…2913) via the x402 "exact" scheme. The maximum amount required per call is 20,000 base units of USDC, which equals $0.02 (USDC uses 6 decimals).
The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance and crypto market data, and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request with no API keys, no rate limits, and no commitments. However, the specific endpoint being listed here (/api/v1/transactions/372/receipt) is not among those advertised on the landing page, and its exact response payload is undocumented.
The x402 challenge was successfully captured (HTTP 402 with a well-formed accepts array), confirming the endpoint is live. No OpenAPI spec, detailed documentation, or example responses were found in the crawl — the docs, pricing, API, and README pages all returned only a "Connect wallet" stub. Because of this, the actual content of the receipt response and the expected POST body are unknown.
Capabilities
Use cases
- —Retrieving a transaction receipt for record ID 372 via a single micropayment
- —Demonstrating x402 payment flow integration on Base with USDC
- —Agent-driven purchase of on-demand data behind a crypto paywall
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can settle USDC payments on Base
- —Use cases requiring no-signup, pay-per-call API access
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume batch retrieval where per-call pricing adds up
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/372/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment on Base to complete.Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint exists and its pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no documented request/response format, no example payloads, and the docs pages are empty stubs. The specific endpoint (/transactions/372/receipt) is not listed among the site's advertised APIs, making its purpose unclear.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —Docs, pricing, API, and README pages all return only a 'Connect wallet' stub with no content
- —The specific resource /api/v1/transactions/372/receipt is not listed among the site's advertised endpoints
- —Request body format and response schema are completely unknown
Citations
- —The x402 challenge returns maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/372/receipt
- —All listed APIs are priced at $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/transactions/372/receipt