x402-gated transaction receipt endpoint on Base, paying $0.02 in USDC per request.
What it does
This endpoint at lowpaymentfee.com provides access to a transaction receipt (resource `/api/v1/transactions/297/receipt`) behind an x402 paywall. The site advertises itself as a platform hosting multiple pay-per-call API categories — data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request, settled in USDC on the Base network. No API keys or rate limits are required; callers pay per request via the x402 protocol.
The specific endpoint probed returns a valid x402 challenge (version 1, scheme "exact") requesting up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals → $0.02) to wallet 0x1A2B…85F3. The response MIME type is `application/json` and the method is POST. The endpoint is live and responding correctly with HTTP 402.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawl. The exact nature of the "transaction receipt" returned by this specific endpoint is unclear, and the broader API surface (AI, finance, utils endpoints) is not documented beyond listing names and prices on the landing page.
Capabilities
Use cases
- —Retrieving a transaction receipt via a single paid API call
- —Demonstrating x402 protocol payment flows on Base
- —Agent-driven micropayment API consumption without API keys
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need keyless, pay-per-call API access on Base
- —Low-cost per-request data retrieval settled in USDC
Not for
- —Production workloads requiring documented request/response schemas
- —Users who need free or subscription-based API access
- —High-throughput batch processing where per-call fees add up
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/297/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment to proceed.Endpoint
Quality
The endpoint is live and returns a well-formed x402 challenge with clear pricing, but there is zero documentation on request parameters, response schema, or what the receipt actually contains. Docs pages are empty. No OpenAPI spec. Effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; the exact payload expected and returned is unknown.
- —The purpose of 'transactions/297/receipt' is unclear — it may be a demo or placeholder endpoint.
- —Broader API surface (AI, analytics, finance, utils) is listed but completely undocumented.
Citations
- —The endpoint returns a valid x402 challenge requesting up to 20,000 base units of USDC on Base ($0.02)https://lowpaymentfee.com/api/v1/transactions/297/receipt
- —All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/297/receipt
- —Docs, API, pricing, and README pages render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs