x402-gated transaction receipt endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides a transaction receipt resource (transaction ID 19) behind an x402 paywall. The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data & analytics, AI & machine learning (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are 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 — `/api/v1/transactions/19/receipt` — returns a valid x402 challenge (version 1, scheme "exact") requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this translates to $0.02 per call, consistent with the site's advertised pricing. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
Documentation is extremely thin — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what the receipt payload actually contains. The platform appears to be a demonstration or early-stage project showcasing x402 micropayments across many endpoint categories, but without substantive documentation it is difficult to assess the quality or completeness of the underlying services.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction ID 19 via a single micropayment
- —Demonstrating x402 protocol payment flows on Base with USDC
- —Integrating pay-per-request APIs without API key management
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need keyless, pay-per-call API access on Base
- —Testing micropayment-gated endpoint integrations
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/19/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with USDC payment proof on Base to access the receipt.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and no examples of actual response payloads. The docs/pricing/README pages are all empty wallet-connect stubs. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —All documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no content
- —The specific resource 'transactions/19/receipt' is opaque — no description of what the receipt contains
- —The platform lists many endpoint categories but it is unclear whether they all function or are placeholders
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/transactions/19/receipt
- —Platform advertises APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com