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 path `/api/v1/transactions/189/receipt`) behind an x402 paywall. The site advertises itself as a platform hosting multiple 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 with no API keys, no rate limits, and no commitments required.
The specific endpoint probed returns a valid x402 challenge (HTTP 402) requesting payment of up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals = $0.02) via the "exact" scheme. The payment is directed to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The response MIME type is `application/json` and the method is POST.
However, the crawled documentation pages (`/docs`, `/api`, `/pricing`, `/README`) all returned only a "Connect wallet" stub with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what the receipt payload actually contains. The site lists many endpoints across diverse categories, but without documentation it is unclear what data any of them actually return. Treat this as a low-documentation listing.
Capabilities
Use cases
- —Retrieving a transaction receipt by paying $0.02 in USDC on Base
- —Demonstrating x402 protocol payment flows for agent-to-agent commerce
- —Accessing pay-per-request APIs without API key registration
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing keyless, pay-per-call API access on Base
- —Low-cost micro-transaction receipt retrieval
Not for
- —Production workloads requiring documented request/response schemas
- —Users who need free or subscription-based access without crypto wallets
- —High-throughput batch processing (no documented rate limits but no guarantees either)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/189/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment to access.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but all documentation pages are empty stubs ('Connect wallet'). There is no OpenAPI spec, no request/response schema, and no explanation of what the receipt payload contains. The listing is essentially a stub with only the payment challenge to go on.
Warnings
- —All documentation pages (/docs, /api, /pricing, /README) returned only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema available — the actual payload structure is unknown.
- —The specific endpoint path (/api/v1/transactions/189/receipt) suggests a hardcoded resource ID; unclear if this is a demo or a real transaction.
- —The site lists many diverse API categories (AI, finance, geocoding, etc.) all at $0.02 — unclear if these are functional or placeholder endpoints.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/189/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 site lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages /docs, /api, /pricing, /README returned only 'Connect wallet' stub contenthttps://lowpaymentfee.com/docs